I'm thinking about buying a 65-66 bug. what should I look out for on these models ?

RUST..dont get cought out with a rust bucket.

Yeah I know about the rust factor, is there anything else I should watch for

Yep rust, bottom of doors, all around front were the doors meet the body. Have a good look around that front pillar area and give it a good tap.
Drive and select all gears, make sure you drive it give the pedal a good squirt. I also like to sit in the passengers seat and go for a drive as well.

Thanx heaps, there is a 67 bug parked in my neighbor's yard so think about buying it

heater channels if carpeted give them a good squeeze, should not crackle

Also rust, Check for rust.