WEST output transformers?

[kegger]

Anyone heard of or have info on some outputs marked.. WEST GO-400?

A recently picked up home brew rack mount stereo amp running (5) 6550
tubes (2) per side in push pull with the 5th doing the regulation it looks like
anyway then wired in pentode has these big ol'e outputs on it's chassis.

Only markings are the WEST numbers, there pretty darn big with the stacks
measuring 2.5" deep x 4" wide x 4.5" tall. Looks like a solid 100w output pair.

(With the layout and rackmount)
Now at first I was thinking some kinda PA or guitar setup with being pentode
but looking underneath reveals they have UL taps as well just not being used.
Most old pa or guitar stuff I've seen on outputs not really made for fedelity do
not usually go the extra mile and have UL taps so they have me intrigued.

Must of had a seperate power supply as there's an umbilical an the only power
on the chassis is (2) filament tranny's and I believe (2) 24v tranny's.

Anyway if anyone could shed some light would be much appreciated.