I agree with the seller...I've never seen one like it. That don't mean much, I'm not a authority here. It appears like a conversion of some sort but it don't look hacked.
I'd love to hear your comments.
https://www.ebay.com/i/292262326389
They were made in house by Western Electric:
http://www.classicrotaryphones.com/forum/index.php?topic=3454.0
Thanks, I hadn't seen that!
How Cool! so, they were made for the Bell retirees? what an awesome gift.... too bad they didn't sell them retail.... good way to use extra parts....