NO! That will almost surely over oil the system, causing all sorts of trouble.
Either on the underhood decal or in the service manual you will find the total capacity for system lubrication. Since the oil travels (and then settles) through the entire system, the trick is to see how much of that oil is in the compressor you’re removing and install the same amount of fresh oil in the compressor. There are guidelines to follow for this, but ultimately the only 100% sure way to get the oil charge right on the nose is to remove the oil from the entire system and start from scratch. Not something a DIYer can normally do, but it wouldn’t surprise me if you have A/C flush equipment available since you’re a professional.
No. A prefilled compressor will almost certainly have PAG oil, and PAG is not compatible with the mineral oil used in your car. Ester oil is an acceptable oil to use in this case when doing a retrofit, but…earlier K cars were poor candidates for drop-in conversion to R134. The heat dump at the condenser was marginal at best with R12, and with R134 there just wasn’t enough thermal exchange to give adequate cooling at idle or low speeds. But by 1993 I think they were getting ready for R134 and may have upgraded the condensers. At least that’s my experience.
Obviously hoses should be replaced at this age as well. Any well-equipped local shop should be able to fabricate those for you. I know the shop I recently left could.