Piece of cake. Probably needs to be recharged, as do most older vehicles. Any A/C system leaks over time, no matter how good. I guess the deal is that it will leak out of the hoses. This takes a very long time though. You need to put a vacuum pump on it and some gauges and see whats up. Suck it down to around the 30" range and then turn the pump of and watch the gauges. Go grab a beer, watch some TV, and scratch yourself, lol. Then you'd come back to see if its held the vacuum. If it holds, you are in like flynn. Load it up with some parts store r-134a that comes with the new oil. You'll need the conversion fittings too. Should take about 2.75 pounds of 134 or so and 6-8 oz of oil. Be sure to get the 134 with the polyol ester oil. It is compatible with the old mineral oil and won't cause any problems. That part store refridgerant is design to work in refit situation just like these.
If it leaks, than you got work to do. You can get a kit with all the O-rings and have at it. Still not better, then probably new hoses are in order.
This whole procedure has to be done by someone who has all the cool toys for a/c. You'll probably have to go to a shop as they have all the equipment and know what to check when they have their gauges hooked it to it. About the only thing you'll be able to do yourself is check the compressor. Look over on the passenger side for a big metal cylinder. Undo the plug on the side of it and stick a jumper in that plug. Than fire it up and turn on the a/c. It probably won't get cold, put the center part of your compressor pullet should begin to move. This would tell you that your clutch is good and your compressor is not locked up.