One minor point- the inserts for the compact GP100 grips (which came on the fixed sight model) are the same as the inserts for the SP101 grips, even though the grips themselves are not the same.
The SP insert may or may not fit the small GP (fixed sight) depending on if the insert has the counter sunk hole for the grip stud.I have some that will enterchange and some that will only fit the SP.