I just replaced my R4 ac compressor and the VIR on my 1974 corvette as well as flushed out the system. (My system was converted to r134a about a decade ago). I added 4oz oil to my compressor (turned clutch by hand to lube up the internals) and I just vacuumed out my system with a pump from oreillys.

Did vacuuming out my system remove any oil from the compressor?
Also can I use the r134a with oil already in the can to recharge or just stick with the 'pure' 134a?

EDIT: (FYI the vacuum pump I used said it had an 'oil mist preventative cap on it and there was some oil in it after I vacuumed it out, it was like less than an ounce of oil)

2nd EDIT: I just figured it out and added additional oil to the system before I rechargded it. It is working well and blowing cold!