Trying to make the title search friendly.....

Temps are rising and the time has come. Here is brief background, with questions to follow.
The Squash was hit in the front at some point, and the condenser was replaced. The AC lines to the condenser ARE NOT CONNECTED, so the system has been open to the atmosphere probably for a year or 2. All components are there. I have a new exp. valve and rec/dryer already [in boxes] and am going back with R12. I do plan on dis-assembling every connection point, replacing all o'rings and flushing out everything with a flush gun.
Questions:

1) What is the effect on the system having been opened to the atmosphere for a period of time. Does this promote rust or scale-type stuff? The AC system in Scar is sealed [small pressure release if I press Schrader valve] so I've been leaning towards using that condenser and some of the lines. What do yall think?

2) I have 3 used compressors. One on the car now, one on Scar, and one I removed from the wagon last year to install a reman [I think it was OK, and exp. valve was my issue]. None are seized. Is there any way to tell the condition of a compressor when it isn't plumbed into a working system? I figure folks will say to just spend a little over a hundred buck and buy a reman, but even $100 bucks adds up.

I can't wait to experience the acceleration of a 240D with the compressor running......

__________________
Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John