Some pics to illustrate this part of the thread!
UA15 SS3D, with larger (11"?) platter extension and tubular arm. First pic.
UA15 SS5G. fourth pic.
Bush used this model in the SRP 31D and SRP41. Pictured:
UA16 (taller, allowed 10 or more records to be stacked) -second pic. Was also made in grey and white.
UA15 (original blue) - 5th pic. This was also made in beige/brown.
UA15 (later black version) - 3rd pic
I have three (blue UA15, UA15SS3D, and a UA16 in my SRP31D)
I should maybe get out more!