Updated: Nov 28, 2022
Colt's gunleather appeared in the very late 1950s and in the beginning was made by a single Eastern maker who was likely Courtlandt Boot Jack, better known to us today as JayPee. All these appear with model numbers prefixed with 'C'.
The best made ones arguably were those made for Colt's by Arvo Ojala's operation (model number prefix 'O') yet these varied between being identical to his standard line to being a custom version of same; such as suede linings on the holster and the belt. The best KNOWN are the many that came from Wally Wolfram's shop (model number prefix W) beginning in the '60s but that came to an end when Wally sold out to Bangor Punta that owned S&W; and S&W Leathergoods was formed from that:
The maker's marks are all different with Wally's being the sole version in an oval styling.
Finally were those for Colt's by Hunter using model number prefix 'H', and a molded rubber holster made by Tayra Corp.
Read more in my book titled "Holstory -- Gunleather of the Twentieth Century -- the Second Edition" that is available at www.holstory.com and printed for you/shipped to you in USA.