you can check this page if you find your proof marks. http://www.singoldschuetzen.de/M08_Allgemein-Dateien/Dateien/M08X36_Beschuss.htm

crown U = Final Proofing
crown N = Nitro Proofing
crown W = shotgun choke bore Proofing
crown S = shotgun cylinder bore Proofing

I´m not sure about, but 2g Sch.P could mean 2 Gramm Schwarzpulver (Blackpowder), this would be equivalent to 31 grains but seems to be a low number...!?

hope that helps a bit
Tom