Here's his page for the 9mm g3c and 9mm g2c magazine sleeves he offers. Yes, g2c mags will fit in the g3c, i recently purchased a g3c and my pt111. Ensure you have more than enough fire power with the promag® taurus® pt111 g2 / g3.
taurus g3c Extended magazine pro mag PT 111 g2 9mm 32 rds YouTube
Pro mag taurus pt111/g1/g2/g3, 9 mm,32 round capacity, steel construction, blue finish
