Hello Ceaser and Welcome,
Since you are in a hurry, I'll give you some immediate feedback.
Watchouts:
1. No known 65 GS's came with a 310, this is a small block and the GS was a big block 401 performance package in 65.
2. Look at the plate on the drivers side door jamb (hinge side). The last set of numbers should match up with the numbers on the block.
3. If this is a coupe or sedan (hardtop or hardtop post) look for a boxed frame. If you need to know what a boxed frame looks like, look at the Gallery section or some of the resto links in this forum and you'll be able to see how it's enclosed.
4. In the VIN, notice the second line - ST 66- Are you sure this is a 65? If it is, it looks like someone may have played musical VIN tags since 66 would mean this is a 1966 Skylark.
5. Look at the fenders. Fender trim differences:
Skylark had simulated vents and is more often referred to as spears because of their shape. They are one piece and are meant to be part of a group of moldings that run down the doors and quarter panels.
Special had three simulated vents and were also cast. These are smaller and consist of three seperate pieces. The Special had no moldings down the side of the car typically unless dealer / owner installed.
GS has a more complicated cast and stainless vent style fender emblem. These are multi piece and square in shape. The GS had no side moldings unless again, dealer or owner installed.
Refer to the Gallery for pictures of each under the GS - Skylark - Special picture groups.
Check the title and see if it matches up to the VIN tag / jamb tag, again if this is a 65 body, then something is up with the plates.
So far everything I'm seeing has sent my "warning light" flashing and personally I'd be a little scared to spend more than the money I'd recover from parting it out especially if you are buying it from out of state and it'll require an out of state inspection... my Spidey senses are tingling and I perdict title issues.
If you need, email me some pictures or post them here and I can give you a better opinion of it.