I'm no expert on these pistols, but have seen a fair number of mil/surp pistols.
Since my PA-63 does not have an "F" at the beginning of the s/n, but a different letter, the most likely purpose for the letter is to indicate the s/n block your pistol is part of -- that is, pistol # XXXX in block "F". For mass produced weapons, this is a simple system to avoid longer and longer s/n strings, and has been widely used with military firearms for over a century.
Since the s/n of your and my pistols both have 4-digits, my guess is that FEG was using blocks of 9999 pistols and going through the alphabet, first with one letter, then a series with two letters, and perhaps even on to a three letter series. Each series would be able to accomodate up to 260,000 pistols (although it is not uncommon for arms makers to skip letters easily confused with numbers, such as I and O).
On the other hand, if someone else has a PA-63 with more than 4 digits in its s/n, then the number of pistols per block and series is simply increased. Some arms manufacturers will "fill-out" low numbers with leading 0s to fit the number of digits per s/n (ie, "0001" is the first s/n), while others will just start with "1" and go until the block is completed. I have no idea how FEG handled this.
Originally Posted by BudDog
Anyone have any idea what the three stamp markings represent on the FEG, PA-63? I am aware of most of the history of this Hungarian Weapon but can't find anything related to the stampings on the frame. Also would be interested if anyone knows what the letter "F" represents at the start of the S/N.
Thanks for any info,