A very nice write up Sheepdog, it's good that it's in the hands of someone that appreciates the history.
The holster is a Jordan River Holster designed by William "Bill" Jordan (retired U.S. Border Patrol) several years back and very popular with Peace Officers in the 70's and 80's. He designed it with a slight rearward cant to ride easier while sitting in a vehicle. I carried the plain black version for about 15 years of my career.