Odd Recoil Plate

First picture is a cast plate I found years ago. Best ICR it was made over seas.

Either way, I just found this one which also looks to be cast in a bag of stock parts inside a box of Handguards.

First pic is the one made over seas IIRC.
Second picture is my recent find.
Has anyone seen a plate like this 2nd one with this square raised lug on top?

Thx,
Charlie-painter777

https://www.milsurps.com/images/impo...DSC04248-1.jpg

https://www.milsurps.com/images/impo...DSC08681-1.jpg

I had one close but not as crude. Quality control be damned!