Well, FWIW, I would be a lot less concerned if it is on the outside than if it were on the inside.

I assume this one has the same frame as my Terminator in which case the grip portion of the frame is more likely to be the same size as a K-frame. Is it round or square? My Terminator has a round butt grip and most K-frame grips fit it. Though some don't because of the location of the hammer spring.

The S&W has a curved flat spring which is off center in the grip frame, but the Astra has a coil spring wound around a strut rod that runs right down the center of the grip frame. So if the grips have a screw that is centered (front to rear), it will likely interfere with the strut and coiled spring.