From 1982 to 1991 G17s were assembled & test fired in Austria. (Later pistols were assembled and test fired at Glock Inc. in Smyrna, GA.) These early production pistols are marked with an eagle and "NPv". The markings are proof marks and inspectors marks as required on Austrian pistols.
The NPv mark means "Nitro Powder proofed". To get this proofmark, a Gun in Austria has to be proofed with 130% loads.
The Pentagon signifies polygonal rifling
LEB - G-17MB - May 2007 - - white box label, ambi mag release