As far as I know the told story, in 1945 in Germany the things happened like follows:
The Allied forces collected all the weapons, also the sport arms or hunting-shotguns and fire-rifle/zimmer-rifle. Not all were destroyed immediately, but the expensive-looking ones and also the sportarms wehrmann-büchse / wehrmanns-gewehre were collected separately. In that offices or storehouses the rifles were separated from the diopters. With wehrmanngewehr (very military-looking!), they proceed like that, they put the lever-bolt out and stored them separately from the rifle in different crates. They wanted, that the arms are at the moment not able for shooting.
In US (or perhaps also in GB), the crates came to different storehouses. Lot of years later, they found again these crates with the fire-rifles, but they didn't look for the crate with the diopters. So the fire-rifles went out without the peep-sights. Nobody knows, where the crates with the peep-sights are went to...
Also the wehrmann-rifles. They put together the lever-bolt and the rifle, but didn't look about the hammered type-numbers. So all the collected wehrmann-rifles (which came back to the shooters) have nowadays different numbers from lever-bolt and rifle. If you find one with equal and correct numbers at all marked parts, you know that this wehrmann-rifle wasn't collected in 1945 by the Allied forces. So it's a rifle, which was hidden stored in an attic or cellar.
Would you be so kind to look about those lost crates with the diopters?
Biggi