Yep, The Freeze-12 cans use standard can adapter threads, so you could screw on an R134a can adapter. My buddies had an r134a adapter on the low side, and regular r-12 on the high side. I borrowed an r134a gauge set and vacuum pump to do the refill. The kit came with an r-12 can adapter though and since I wasn't hooking up the high side line, I connected the can adapter to the high side gauge and sealed the center line to do the charging. Worked great.

-Todd
1987 Montero 2.6l 5-speed (Sold...but I still miss her)
2008 Jeep Patriot Sport 4x4