I would recommend using Resaissance Wax on the holster. It is used by many museums and The Smithsonian Institute. Here is a link to the product and some of its uses.
http://www.restorationproduct.com/index.html They also sell it at Midway USA.
I will point out that the holster has lasted a long time. If it is as old as the gun it has lasted 40-50+ years. Not to shabby for a holster. Mine might last that long too with normal use, but if they fall apart after that time, don't call me as I will probably have been dead long before then. I'm pretty sure I will look much worse than the holster.
Generally speaking do not put anything on a holster that will soften the leather. Especially for a molded holster. Neatsfoot oil will soften leather. Read the label for most things you put on leather and you will see that it says that it will soften leather. So for some things that is OK, but for a molded holster it is not. If you soften the holster with products that soften the leather, the holster will likely lose it retention and molding over time. The holster shown does not have much if any molding. But if it softened too much, it could collapse when the gun is withdrawn.
Also the strap on the holster looks especially worn where it goes over the hammer, and if used allot it could break. I assume the wearing has weakened the leather and I'm not sure any product will add more strength.
Renaissance wax will help it but there is lots of wear on the holster. It will likely still have some darker and lighter areas even after it is applied. It is supposed to be used sparingly too! It has many uses and is good to have around.
