If it looks as good now as it did two years ago, and runs accordingly, I’d say 6-8k easy; more if presented well. Patrick
That is a nice looking Skylark ya got there! Bonus for someone like me that would only buy a car with AC, too. I use NADA a lot when looking for a vehicle. They have a classic car value estimator now, too: https://www.nadaguides.com/Cars/1969/Buick/Skylark/2-Door-Hardtop/Values They do not differentiate between a post and non post car, though. Some tribal knowledge may help with that. I usually go to Kelley Blue Book too, but their values only go back to 1992. Hope this helps.
Not to split hairs, but not a skylark. Special Deluxe sounds so fancy! https://www.nadaguides.com/Cars/1969/Buick/Special-Deluxe/2-Door-Sedan/Values