From my experience, Yes.
I run 4 different brands of mags in my SVs: STI, Rescomp (requires some fitting), SV old styles and SV new styles. All run flawlessly.
The best remains the newest SV mags. All the others are used for training.
What did you do to the rescomp mags? Im having problems with my rescomp mags when im still using my stock sti grip. It wont drop free. After i installed my advance performance grip, it just dropped free!