Is there any way to identify OEM Western Electric / AT&T single slot faceplates?

[MaximRecoil]

As opposed to aftermarket replacements? I know the older ones had the Bell System logo inscribed in the lower right-hand corner, but what about the ones made later (presumably under the AT&T name)? Was there a part number on the back or anything?

[ESalter]

I seem to recall they had "WE" cast into the back, but I could be remembering wrong, it's been a while.  I've seen some from the AT&T Technologies era that said "AT&T" on the face instead of the bell logo, but those are pretty scarce.  I have a WE one without a bell logo on the front, I'll take it off and see what it looks like on the back and get back to you.

---Eric