Yes. If the piece of equipment has a plate with the weight or weight rating it can be used with the weight rating of the towing unit. One could also weigh the combination and use that weight to determine whether the combination exceeds 10,000 pounds. The greater of the GCWR or the actual combined weight would be the value that would be used to determine applicability of the regulations.
An interpretation from the Federal Motor Carrier Safety Administration is below:
A company has a truck with a GVWR under 10,001 pounds towing a trailer with a GVWR under 10,001 pounds. However, the GVWR of the truck added to the GVWR of the trailer is greater than 10,001 pounds. Would the company operating this vehicle in interstate commerce have to comply with the FMCSRs?
Guidance: §390.5 of the FMCSRs includes in the definition of CMV a vehicle with a GVWR or GCWR of 10,001 or more pounds. The section further defines GCWR as the value specified by the manufacturer as the loaded weight of a combination (articulated) vehicle. Therefore, if the GVWR of the truck added to the GVWR of the trailer exceeds 10,001 pounds, the driver and vehicle are subject to the FMCSRs.