You can use shell holders from any of the major manufacturers on your RCBS press. I've got them from RCBS, Lyman, Lee, C-H and Redding, and they all work. Just be advised that changing from one shell holder to another in the same caliber, even of the same brand, can change how far a case is pushed into a die. They're made to max./min. tolerances, and as long as they're within those parameters are considered "in spec.", but there may be a few thousandths of difference. It's not as critical with pistol calibers as it is with bottleneck rifle calibers, but is a fact of life.
Hope this helps.
Fred