Formerly known as xpd54.
The opinions expressed in this post are my own and do not reflect the opinions or policies of my employer.
www.gunsnobbery.wordpress.com
I'd think about using epoxy. Lots of people like Devcon 11010 for bedding rifles. I used it to bed the front sight on my GP100 (there's a thread around here somewhere). I'd prep one of the grips to have it stick, and the other (and the frame, of course) to release it. Will have the same hardness as the G10, look kinda right (dark grey), and you can shape it by sanding, etc. to blend perfectly with the shape.
.
-----------------------------------------
Not another dime.
Actually, I like them as is. The gap doesn’t interfere with function and the square butt provides important extra area for your support hand. I’d also point out that the grips are designed for right handers only not shaped to be ambidextrous.