I just installed a repro "Gold Strike" backglass into a game I'm bringing to the White Rose show. It didn't want to fit width-wise. I laid the new glass over the original one, and saw that it's about 1/4" wider. It is also thicker than the original one.
In order to make it fit, I began to chisel off the small wooden block in the backbox, which stops the glass from moving to the right. I must have tried fitting the glass at least four or five times after each round of chiseling, but it still wouldn't go. Finally, I removed the plastic stop on the left inside edge of the back box, which is held in by one screw. Now, the glass fit. I noticed that the plastic stop had a taper to it which corresponds with the taper of the wedge head lightbox. So, I slid the wedge down along the left edge of the backglass, until it rested snug again the glass. Then, I marked a new hole for the screw, removed the glass again, and reinstalled the plastic wedge slightly above where it was originally. Now the glass can't shift laterally, and luckily the alignment with the score reels is perfect.
As I said, the new glass is also thicker, so the lightbox insert fit very tightly against the glass when I swung it closed and locked it with the lever. I guess I could have used some washers behind the hinge brackets to give it a little more room, but I'll leave it snug.
Just thought I'd share this, and has anyone else here had problems fitting a repro backglass into a game?