Ebay is just about the best place to find Colt catalogs these days. Wilkerson also has (or had) a lot of catalogs for sale. Good luck in your quest. I have lots of Colt paper as I collect the stuff. Some of the old catalogs cost as much as the guns.
rj; a "cheaper" way to get the "catalogue",is to buy "Shooters Bibles" or "Gun Digests" from the years you are interested in. Those 1960s have NOT reached the "collector" price ranges yet,and I've seen most in the $5.00 to $10.00 range,less if they are "well used". There might be some "options" left out in the material reprinted from the Colt(and other brands)catalogs in these issues,but you will save $$$,and get info on other "vintage" items and accessories in the "bibles" and "digests" from those eras. "Genuine" catalogs are very pricey;just check ebay! Good Luck; Bud
I have found the Shooter's Bibles to be a very poor reference for Colts. Gun Digest's are better. The problem with them is they are so darn big and take up so much space.
Collecting the catalogs is a great hobby! You can fit an awful lot of catalogs in a single filing cabinet drawer.
The problem with the 60's catalogs is that they frequently don't have a date until around 1968. The early 60's catalogs are okay and are dated. Colt didn't really start publishing nice post-war catalogs until 1969. The 56 is great. There is such a huge gap in time between 56 and the late 60's in terms of catalogs. The ones that are available are not very pricey yet for anything after 1960. Enjoy!