This is the FEDERAL statute taken from the FMCSA website.
I belive it says that your company name & USDOT # is all that is required.
Where does it say the MC # is required?
§390.21 Marking of CMVs.
(a) General. Every self-propelled CMV, as defined in §390.5, subject to subchapter B of this chapter must be marked as specified in paragraphs (b), (c), and (d) of this section.
(b) Nature of marking. The marking must display the following information:
(b)(1) The legal name or a single trade name of the motor carrier operating the self-propelled CMV, as listed on the motor carrier identification report (Form MCS–150) and submitted in accordance with §390.19.
(b)(2) The motor carrier identification number issued by the FMCSA, preceded by the letters "USDOT".
(b)(3) If the name of any person other than the operating carrier appears on the CMV, the name of the operating carrier must be followed by the information required by paragraphs (b)(1), and (2) of this section, and be preceded by the words "operated by."
(b)(4) Other identifying information may be displayed on the vehicle if it is not inconsistent with the information required by this paragraph.
(b)(5) Each motor carrier shall meet the following requirements pertaining to its operation:
(b)(5)(i) All CMVs that are part of a motor carrier's existing fleet on July 3, 2000, and which are marked with an ICCMC number must come into compliance with paragraph (b)(2) of this section by July 3, 2002.
(b)(5)(ii) All CMVs that are part of a motor carrier's existing fleet on July 3, 2000, and which are not marked with the legal name or a single trade name on both sides of their CMVs, as shown on the Motor Carrier Identification Report, Form MCS–150, must come into compliance with paragraph (b)(1) of this section by July 5, 2005.
(b)(5)(iii) All CMVs added to a motor carrier's fleet on or after ATE Day="3" Month="7" Year="2000">ATE Day="3" Month="7" Year="2000">July 3, 2000ATE>ATE>, must meet the requirements of this section before being put into service and operating on public ways.
(c) Size, shape, location, and color of marking. The marking must—
(c)(1) Appear on both sides of the self-propelled CMV;
(c)(2) Be in letters that contrast sharply in color with the background on which the letters are placed;
(c)(3) Be readily legible, during daylight hours, from a distance of 50 feet (15.24 meters) while the CMV is stationary; and
(c)(4) Be kept and maintained in a manner that retains the legibility required by paragraph (c)(3) of this section.
(d) Construction and durability. The marking may be painted on the CMV or may consist of a removable device, if that device meets the identification and legibility requirements of paragraph (c) of this section, and such marking must be maintained as required by paragraph (c)(4) of this section.
(e) Rented CMVs. A motor carrier operating a self-propelled CMV under a rental agreement having a term not in excess of 30 calendar days meets the requirements of this section if:
(e)(1) The CMV is marked in accordance with the provisions of paragraphs (b) through (d) of this section; or
(e)(2) The CMV is marked as set forth in paragraph (e)(2)(i) through (iv) of this section:
(e)(2)(i) The legal name or a single trade name of the lessor is displayed in accordance with paragraphs (c) and (d) of this section.
(e)(2)(ii) The lessor's identification number preceded by the letters "USDOT" is displayed in accordance with paragraphs (c) and (d) of this section; and
(e)(2)(iii) The rental agreement entered into by the lessor and the renting motor carrier conspicuously contains the following information:
(e)(2)(iii)(A) The name and complete physical address of the principal place of business of the renting motor carrier;
(e)(2)(iii)(B) The identification number issued the renting motor carrier by the FMCSA, preceded by the letters "USDOT," if the motor carrier has been issued such a number. In lieu of the identification number required in this paragraph, the following may be shown in the rental agreement:
(1) Information which indicates whether the motor carrier is engaged in "interstate" or "intrastate" commerce; and
(2) Information which indicates whether the renting motor carrier is transporting hazardous materials in the rented CMV;
(e)(2)(iii)(C) The sentence: "This lessor cooperates with all Federal, State, and local law enforcement officials nationwide to provide the identity of customers who operate this rental CMV'; and
(e)(2)(iv) The rental agreement entered into by the lessor and the renting motor carrier is carried on the rental CMV during the full term of the rental agreement. See the leasing regulations at 49 CFR 376 for information that should be included in all leasing documents.
(f) Driveaway services. In driveaway services, a removable device may be affixed on both sides or at the rear of a single driven vehicle. In a combination driveaway operation, the device may be affixed on both sides of any one unit or at the rear of the last unit. The removable device must display the legal name or a single trade name of the motor carrier and the motor carrier's USDOT number.
[53 FR 18052, May 19, 1988; 53 FR 27689, July 22, 1988, as amended at 53 FR 47543, Nov. 23, 1988; 55 FR 6993, Feb. 28, 1990; 57 FR 3142, Jan. 28, 1992; 60 FR 38744, July 28, 1995; 62 FR 49942, Sept. 24, 1997; 65 FR 35296, June 2, 2000]>>