Does the front sight on your 92 even come off? Look at it closly to see if it has a dovetail. Most do not, I am fairly certain that the 92 is not removable, the Elite II are removable (*again from memory). Usually the slide will say "vertec" if it is removable, otherwise, you have 2 options.
First, is there use to be a company, whos name is escaping me right now, but they will drill the existing sight to add a tritium tube. The other option is to send the slide off to a gun smith to get the front sight cut off, then the slide dovetailed. Then refinish as required, then install your sight. But either way you are sending the gun off, since most hobbyist can not do either mod.
This is one of my Berettas, as you see it has a vertec slide on an elite III frame, picked this up a year or two ago when tanner guns had a run made for some employees, 2 of the 50 went up for sale. I scored one, even at a great price. But you can see the "vertec slide" on a non vertec frame. Due tot he vertec slide, the front sight was already dovetailed.
Also Beretta sights are a PITA to remove. Just giving a you a forewarning. Best of luck with your adventure.