That's besides the point as the compressor has already locked up. Unless it just up and broke all at once, then you're probably going to have contamination of the system. If it just had a hard part suddenly fail and lock up, you may be okay. However if the system ran low on oil, or a bearing gave way causing increased drag, or a piston gave up the ghost, then as it dies over time it starts introducing debris into the system.

On my 1995 Caprice, when the compressor locked it also destroyed the ac clutch. I mean it blew the clutch clean off the front of the compressor - all I had was jagged metal sticking off the front, but the pulley still spun. I bought a new GM compressor, PAG oil, drier, and orifice tube. I also bought a bunch of A/C flush. Thankfully I work at ALLDATA where there are a bunch of ASE certified mechanics that would rather sit in front of a computer these days than turn a wrench. So one of them changed the compressor for me. When he started checking the lines he found that the condensor was clogged badly. I located one on a forum and drove 130 miles to pick it up out of a donor car. After that, he filled the system with PAG oil, evacuated the system with a vacuum pump, let it set to make sure it held a vacuum and then began filling with R134 (it was R134 from the start). Worked fine afterwards, never had another problem with it.

I'm only trying to give you some advice so that you don't do a compressor slap and think you're good to go. Many places will not warranty a compressor without a drier and orifice tube at the minium. If you find any metal, backflush everything. If anything seems restricted, plan on replacing it with a new or working used part.

I'm a good mechanic, but when it comes to HVAC it's one area that I don't have training or equipment to deal with it on my own. Also things like changing a compressor on a Caprice is a royal PITA, but these mechanics with 50k in tools have every wobble socket known to man, making the job easy. Thankfully my buddy at work did two compressor swaps and charges on two different LT1 Caprices free of charge. Sweet!

If you want your A/C to work again and don't have the tools or know of someone with them and the knowledge, pay someone to do it right the first time.