RIA 1903 S/N 398186

I recently purchased a RIA 1903 with serial number 398186. From information on the Forum and links to other sites, I determined that this was a Receiver manufactured in 1918. It has a SA barrel dated 5/18. I assume this was a batch of Receivers shipped to Springfield Armory to finish a completed rifle. As I understand it quite a few Receivers in this serial number range went to Springfield. So wondered if it is likely a correct Receiver/Barrel combination for this completed rifle. I have not received the rifle yet, but will post pictures when I do. The gun also has had a Lyman Peep Site (48S) added. I know it is not likely that it was arsenal installed, but wanted to know if possible in this vintage? Rifle has the original 1903 barrel mounted sight still installed and appears to have the original blade front sight. Thanks for your help.
Jim Pearson

The peep would be after service for hunting. Not a military option. Hard to say about the whole thing, many were put together after the fact from parts. We'd love to see it when it arrives.

I received the RIA M 1903 SN: 398186 and have attached some pictures. I think that the RIA Receiver was likely delivered to Springfield for completion of the gun and that the SA barrel is correct for the rifle as initially completed. After research I think the Lyman 48S sight is an older sight and likely installed after the second world war. Would you please look at the pictures and give me your observations on the weapon. The sight is labeled 48S and 1903 a3. I removed the sight and plugged the stock inlet, no glue, so the plug could be removed if someone wanted to re-install the sight. The mounting holes in the receiver are plugged with blued 6X48 plugs. You can see the stock inlet and the plugged holes in one of the pictures.