I'll go ahead and answer my own question and to provide a reference for future CZ-70 owners:
No, CZ-50 grips are not completely interchangeable on the CZ-70 without minor modification if you want the decocker to work. You will have to grind down on the grip just under the safety/decocking lever ever so slightly to give it enough room to properly function. The grips are ultimately, in my opinion, much more comfortable and better looking than the stock CZ-70s, but I just wanted to let everyone know who thinks this is a simple swap job.