A/C overhaul advice sought

[BodhiBenz1987]

So, my 87 300D is in extreme stages of disassembly for rust repair and some other "while it's out" jobs. The whole interior except the dash and steering wheel is out. It's occurred to me that anything I need to with the climate control, now is the time.
The A/C has not worked in the car for at least 15 years, which is about when my dad gave it to me. I don't know what didn't work and he doesn't remember, but I believe the compressor was bad. And there's a leak somewhere because when my mechanic checked a few years ago the system was empty (I just decided to keep driving it without A/C for the time being). If I'd been smart I would have taken it to be diagnosed while it was still running so I knew what to replace. Now I don't think there's really any way to find out, is there?
Anyhow my question is: are the odds of it being the evaporator strong enough to just replace it on principle while I have so much out? And, is there any way I can tell if it's the culprit with the car in a non-running state?
The evaporator is expensive and the job looks like a nightmare (though there are useful DIYs to help me), on top of the body nightmare I'm already dealing with. But I'd hate to put it all back together with my nice re-dyed interior and then find out the evap leaks, you know? Because right now I've already done several steps of the nightmare job, and there are no seats in the way or carpets to get coolant or crud on.
Thoughts?