In that case, you will need to add oil. The big question is how much. Undoubtably, some is still in there, and you don't want too much oil. If you can flush the system and start fresh, you'll know that it's correct.

The correct quantity of refridgerant should be listed on the tag under the hood. I believe that the oil quantity is specified in the climate-control diagnostic manual. If I get a chance, I'll try to look it up.