US stamped leather saddle bags

My grandfather was an auctioneer back in the 1960-80s. He left these to my father, who recently passed away, and my father left them to me.

They look like they are either from the civil war or WW1 era based on internet searches but I'm not exactly sure which or how to properly date them.

Their interior pockets are a thick heavy canvas on both interior pouches. One side has 2 small interior pockets (see attached pic 2) and the other is just a large pouch. Both sides are stamped with US on the outer sides.

There are no other markings that I can see anywhere, although maybe once they get properly cleaned and if I know where to look, I'll be able to find something.

I'm looking for advice on how to properly clean them, oil them and store them to save to pass on to my own child with the backstory and hopefully accurate information on the age. I have read conflicting advice on how to clean them without causing any damage. I know they are quite old and I do not want to take any chances of causing damage to them.

I am limited to just the 3 pictures (I couldn't get 4 to upload) but if there's anything specific that you would like to see, I can update the attached pictures, just leave a comment of whatever picture request you may need.