It all depends on the particular look you want. A lot of stuff in the 60’s and 70’s was shot on film stock, so you might want to go with a film stock setting (Technicolor for example) if that’s what you want, plus a lot of footage was shot with lower resolution video cameras (whites a bit blown out, poor color saturation, scan lines), so that’s a different look. The film stuff might have things going on such as gate weave, dirt and hairs passing through the gate, and a slower frame rate, which would give a “softer” look, while the video stuff would have different color footprints.
You’d get the most control using Red Giant’s Magic Bullet Looks, but it’s expensive. Here’s some free film looks:
https://www.premiumbeat.com/blog/free-film-filters-plugins-after-effects/
If you want to do it the hard way, and learn something new, here’s a Creative Cow thread on doing just that:
https://forums.creativecow.net/archivethread/2/94105
Joe Bourke
Owner/Creative Director
Bourke Media
http://www.bourkemedia.com