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https://www.milsurps.com/images/imported/2019/09/sl1600-9.jpg

Common to see Ordnance Flaming Bomb on early S'G' trigger housings.

I believe-
IP had the complete circle tooling hole. And...

GIUSBOB,
How bout this idea......
Lets call it a IP-S'G' made Trigger Housing.

Reply from link below...........
This first one sound familiar ?

".....there was possibly a "transition"...

The S'G' from the auction looked very refinished to me. Had just enough finish wear to show the light contact rub points from being in a stock and from being attached to a receiver. Add a few hammer...