Need to know the dimensions of the rear dovetail (series 70-80 Govt. 45 ACP).
Measured dimensions (caliper) from a "real" Series 70:
0.348" wide across bottom of dovetail
0.237" wide across top of dovetail, measured at top C/L of slide
0.110" deep, from top C/L of slide to bottom of dovetail cut
These are the dovetail slot dimensions, not the sight. Approximate only--worth what you paid for them. Good luck.