Are they the side release mount and rings?
I have one of these mounts on the 1903A3 that Mr.Jaeger sporterized for my grandfather back in the 1950's.
His nephew trained under him,and owns New England Custom Guns.I needed a set of 1" rings for the mount,and it took a while to track down a set.
I got them from New England Custom Guns,and they also told me that they still have complete mount sets for sale.
New they are not cheap,but who knows what they are worth used.