Trigg,, I agree. There were some POW made. The shields and devices were usually sand cast. Very simple made and not in great quantity's. .The AL cast Lappland shield was made at wars end,, postwar.
The more/longer postwar the more modern construction methods would have been used.. The late date of the ring,,the quantity , method,etc. is why most believe they are after the war..

Evgeniy,,yes a bad time for a nazi ring, especially a foreign volunteer! I emailed Jan and waiting to hear if he knows exactly where they were found and what the material is...