mccobb or umanoff  

Hello Everyone
I have a question about these chairs I have
they both have the same chair glides but from what I understand one is made by mccobb (white chair) and the yellow ones are made by umanoff.

I have seen many reffrences to the white chair being mccobb on ebay 1stdibs and other places. However I did have soemone tell me when I sold mine that they were made by woodard which I own a catalog that shows a similar style but not the same called the Allegro line.

The yellow chairs I assumed were also mccobb since they had the same chair glides also pictured but I was walking down warren street in hudson last weekend and see them in a shop window. when I asked about them I was told they were umanoff which kinda would make since since there was an umanoff chair that i purchased from the same estate. but why would they have the same chair glides.

Any info? thanks