The question isn't as daft as it sounds. The origional 92 had the funky Beretta type of mag catch located at the bottom rear of the left grip panel. You'll notice most factory 92 mags still have a cut out in that spot. Anyone with a Beretta 950 will know the style I'm talking about.
JB, if the mags in your hand have the cut outs on either side on the front of the mag towards the middle, they will fit in a 92fs. If they don't, forgetaboutit