8 lug wheel dilemma... Hmm. Wrong wheel or mis-stamp, or something else?

[jocko]

So, I scrounged all over town and found 6 total 8 lug 16" chev wheels from mid-80's C20s. 3 of them were out of round when I checked them at the local tire shop, so returned them and kept the 3 you see here.

Here's my problem - the goal is to get a full set of 16.0" x 6.5" wide 8 luggers from mid-80's chevs.

ALL 3 wheels had 16.0" tires mounted, confirmed before buying (tires still on). Very hard to find because most junk in the yard had 16.5" wheels.
Once they dismounted the tires, I confirmed with a measuring tape that wall were 6.5" width and the correct hub center opening. And visually, the vent windows and shape of the rim itself is identical.

So, I get em home and do a little wire wheelin' to see if I can find the stamps for the size just as one FINAL check...

I know the pics are hard to see, sorry, but this is what they say:
The first two read (left & middle): 16 x 6.50 L
The last one (far right): ?6.5 x 6.00 (? is unreadable)

So, if I were to take it at face value, I'd assume the third (on the right) is a 16.5x6 - NOT what I was looking for.

BUT it had a 16" tire mounted and inflated and sealed (and was part of a set of 4 wheels on an 85 burb). What the.... They are all clearly 6.5" wide inner rim lip to inner rim lip and the outer rims line up perfectly when they are stood up next to each other. Can't really measure mounting diameter accurately, but they stack up exactly the same on top of each other which would make it appear their diameters are all the same.

Thoughts? I'm now wary to mount a tire on the 3rd wheel... I realize I shouldn't mix 16.5 wheel with 16 tire or vice versa, but EVERYthing except the stamp indicates the 3rd wheel is also a 16" rim.