Yes. Call Ruger and tell them what your problem is. You will probably need to take a micrometer and measure how tall your current front sight stands above the rib, to provide them with a point of reference.
In your shoes though, I would just take a file and a bottle of cold blue to the range, and file a VERY little off the top of the front sight, taking great care to keep it perfectly square. Shoot and confirm zero, and then file again if necessary.
Here's an
article I wrote a couple of years ago on sorting out a 3" GP-100 that needed regulation in both directions, as well as having some other problems. Please note that bullet weight can have a noticable effect on where your bullets strike, in the elevation axis. If you are shooting 110-125 grain bullets in that gun, switching to 158's will probably raise your POI enough to correct the problem. If you are already shooting 158's however, a shorter front sight will probably be necessary.
Congratulations on a fine sixgun- I love fixed-sight revolvers, and the GP is one of the best.
