Don't be afraid to try those puppies with PC but no gas check. I have done a limited amount of testing (three different guns in two different calibers, 15 rounds or so each) GC shanked boolits three different ways... GC before PC, GC after PC and just PC without a GC, I can find no difference or betterment in any of them = once PC'd anything else is a redundant operation.
I should caveate the above statement with the comment that I haven't "hot-rodded" any of these boolits above 17-1,800 fps so if you plan on shooting them faster you may not get the same results.