Very difficult to upgrade. Very few manufactured in 1964, fewer yet were imported into the United States. One of the late-war mismatched PP pistols which is proper for this period. Made and assembled in the closing months of the war in 1945. No proofs of any kind.
Condition is excellent with some scuff marks and evidence of hasty assembly.
Magazine is original wartime Walther with the finger extension. These are getting hard to find. On Order Webley Junior .177 Air Pistol. This is a quality pellet pistol with rifled barrel. Excellent condition with minor wear and freckling.