I wouldn't since R-134A is already being eliminated, and has been for years in Europe and Canada. I use HC refrigerant in all my vehicles now, even the 1996 and 2002 after compressor failures. But, read the supposed fears first and think for yourself. Some people imagine it can "explode", though that is un-technical and even a fire has not been recorded in millions of car's usage for decades. I use Duracool, but Enviro-safe and R-12 HC are others. Compatible w/ R-12 mineral oil, but I use better PAO 68 oil in all mine, since more efficient and doesn't absorb moisture.
I would keep using the RV-2 compressor since changing that in a slant is tough. My 64 slant came w/o AC and I didn't want the RV-2 beast. You can find a long post giving all options in this forum. I ended up making custom brackets for a Sanden, but still have the 78 Volare Sanden brackets if I ever change to power steering, and they would fit better in your wider engine bay than my 1964's. BTW, there isn't really such a thing as an "R-134A compressor". The only thing that varies is the oil fill they come with, and that can be flushed.