Below are the details on the sight cuts used on STI Pistols.
Front Sights: STI uses the STI/Heinie dovetail – 60° x .300″ width
Rear Sights: Rear sight varies based on model but would be LPA, BOMAR or NOVAK.
Image Source : http://stores.kensight.com/common-1911-sight-dovetails
LPA vs BOMAR
Image Source – https://www.egwguns.com