It is possible, that members of a caste are not permitted to practice specific caste skills
It is possible, though it is seldom the case, that members of a caste are not permitted to practice specific caste skills, though they may be permitted to practice subsidiary skills. For example, one who is of the metal workers might not be permitted to work iron, but might be permitted to do such things as paint iron, and transport and market it. Caste rights, of course, such as the right to caste support in time of need and caste sanctuary, when in flight, which are theirs by birth, remain theirs.
The women of a given caste, it should be noted, often do not engage in caste work. For example, a woman in the metal workers does not, commonly, work at the forge, nor is a woman of the builders likely to be found supervising the construction of fortifications.
Fighting Slave of Gor, p. 309-310