If that aftermarket sunroof bothers you, that will be a $1000-1500 fix. "A" pillar and drip rail rust is another area that L-bodies are prone to rust. Like Johny says, wheel well rust leads to front floor rot as water has no way out once it enters the cabin. It finds a way out only when the floor rusts out.
Non-AC car is a deal breaker for some on resale. Easier to work on car without it though.
Decals are wrong (not OEM or even good reproduction) if that is a concern.
Are you and the seller sure it is a 85 and not an 86? The reason I ask is 1985 would NOT have rear 3rd brake light with crooked rear wiper. Either the rear hatch has been replaced with 86+ hatch, or the car is an 86. 85 VIN should have F for tenth digit or 86 will have a G for tenth digit. Also the 85 should should have 287 G-head, while 86 should have 782 swirl head. Lots if people get the two years confused, but there were a number if significant changes to drivetrain.
1985 is a good news bad news thing. Bad news it has 6 bolt flywheel and crank and 10mm headbolts, Good news is it has heavier, stronger rods than the 86-87 turbo L-bodies. The 85 is also a G-head (closed chamber head) vs. the 86 and later swirl fast burn head.
Fairly rare color combo. Black with silver is far more common, than black with red interior.
How does it drive? If it drives good, it will be a fun car, if it runs poorly, or doesn't run at all, it could be easy to fix or it could be a money pit.
Attachment below shows the 85 and 86 rear wiper/brake light changes on decklid.