Historical source for these knee cops?

[C. Gadda]

See picture. I believe based on the maker that they are "real" but am stymied at finding a period source for them. I've gone through a few sources but without finding much. Anybody seen this before?

[human]

mabye a side view would help?

[Len Parker]

https://archive.org/details/recordofeur ... ew=theater I'm never sure with old armour books whether this stuff is legit or not.