From what I've seen around, I'm guessing 60s. I want to fix it up with modern components and paint it. Would i lose a lot of value by doing this? I paid $30 for it, so it I'm not exactly in the red, but I might try to sell it after it's clean and ridable.
The original paint and graphics might get more dollars than a new coat of paint. The cost of new components would probably cost more than the bike would sell for. It looks like the chrome will clean up and if the wheels are straight, just a new set of 26 x 1.75 tires and new seat would be all to do to it, to get the most money out of it. Maybe touch up some of the white paint. You would still come close to breaking even though.
Depending on your market, top dollar for that bike might be $100 if you're lucky. Paint isn't going to make it worth more and it may drive away someone that wanted it because it's a cool old bike. If you just want to flip it, just fix/tune anything that needs attention and post it on CL.