[bgg]

Yes. See rule below:

R33
The integral mechanical and electrical system of any motor may not be modified. Motors, servos, and electric solenoids used on the ROBOT shall not be modified in any way, except as follows:

The mounting brackets and/or output shaft/interface may be modified to facilitate the physical connection of the motor to the ROBOT and actuated part.
The electrical input leads may be trimmed to length as necessary.
The locking pins on the window motors (P/N: 262100-3030 and 262100-3040) may be removed.
The connector housings on the window motors (P/N: 262100-3030 and 262100-3040) may be modified to facilitate lead connections.
The Integrated Encoder Module (P/N: 276-1321) may be installed on the VEX 2-wire Motor 393 (P/N 276-2177).
The VEX 2-wire Motor 393 (P/N: 276-2177) gears may be changed or replaced per the Supplier instructions.