I obtained a US Revolver Co 7-shot .22. It has a serial number of D23207 stamped in the handle under the removable grips and the words "U.S. Revolver Co" & Made in U.S.A." stamped on the top with no other markings. Can anyone tell me what year this gun is or where I can look it up? I assume this gun is not worth very much especially given its condition. I have never fired it but it appears to be in sound condition to fire.