We have been using our modified robotiq_description rather than the binary version of the same. Modifications had to be done for accommodating the gripper with the real robot.
It will not make sense to clone the complete ros2_robotiq_gripper package because of it's dependence with the serial. Since there is a custom setup, the workaround would be to have the gripper_xacro description maintained as part of the ROX package, while the meshes needs to be relied upon the robotiq_description from the binaries.
@AdarshKaran what do you think?