The 92 FS differs only one way. Above the left grip plate,and between the grip plate and the frame you will see a large circular pin. That is the hammer pin.The diameter was increased and a corresponding groove cut into the left rear portion of the slide. That was intended to " capture " the slide in case the rear of the slide should separate. The 92 F doesn't have it. Look at the rear left lower corner of the beretta slide and you can seen an extra groove at the bottom that the girsan does not have. Prior to its widespread adoption by the U.S. military, questions were raised in a 1987 General Accounting Office report after an incident where a slide failure on a Beretta M9 injured a Naval Special Warfare member, and two more failures were later observed in additional testing. These failures included both military and civilian Beretta models with very high round counts, and after investigation they were deemed the result of ammunition supplied by the U.S. Army which exceeded the recommended pressures specified by NATO but nonetheless provoked a modification in the M9 design to prevent slide failure from causing injuries. That brought about the M9A1 IN 2006 as well as the 92FS, neither of which the girsan is modelled after, so it's a moot point. The slides did not fail on M9 and 92F (that girsan is modelled after) that fired the ammo that we will likely be firing (i know i won't be firing +p or +p+)Not to mention how long it will take me to get the mileage on mine that they had on those. I wouldn't worry about it. I'm more concerned if all the Beretta parts fit it for sure as i don't want to send for a $100.00 trigger or hammer for a Beretta and find out it doesn't fit and be stuck with it. anyway my finger is getting tired and i need to save it to go shooting. just regularly change your recoil spring before it gets tired. this is a key part and can really affect the life of a slide.During one test of twelve pistols fired at Beretta U.S.A. before Army supervision, Beretta-made M9 pistols shot 168,000 rounds without a single malfunction. if the girsan can go 1/4 that,i'll be happy.