Oh, I meant to comment on your grips. They appear to be from the 1920's but have had the checkering sanded away. S&W marked the back of the right panel with the serial number of the gun because they were hand fitted to the grip frame. There may still be a penciled number on your right panel but, after all this time, it may be erased. If you can give us the number, we can give you an approximate date the grips were made.
To free up the action, I suggest you remove the grips and immerse the whole gun in auto transmission fluid for a few days or weeks. Then take some aerosol carb/brake/parts cleaner and spray the gun down. Spray into the action through the hammer or trigger openings until the effluent runs clear, then put 5 drops of gun oil into the action to lubricate it. That should make it operate a lot smoother. It should also loosen up any rust on the outside and allow it to be wiped away with a soft cloth. You can polish the nickel if you like. Flitz or Mother's Mag polish works pretty well.
You can use neatsfoot oil on the holster. But it is not recommended as a long lasting conditioner.
Blackrock Leather N Rich was recommended to me many years ago and I still have the can I bought about 12 years ago. It doesn't change the leather color or damage the stitching.