Hello Tom.
Yes, you're right: my pistol is rebarreled (better, rechambered) in 9X21 because here 9 para is illegal, but the barrel is matching and original (marked 8.82).
The markings should be germans, post-war period; the eagle seems to be Bunds Republik type, and the shield w 3 crowns the symbol of Koln test bench.
Here is an adress with a good database for european markings and codes; it's in italian, if you need I'll help you:
http://www.earmi.it/armi/database/codicige.htm
Marzio