US General 56" depth?

[WunTon]

I've searched for what feels like forever and I cannot find a definitive answer on the depth of the series 1 56" boxes. I've tried video reviews, forum reviews, everything but I can't find the answer. I know someone here knows if the series 1 boxes were 18" or 22" deep. I've got an opportunity to pick up a series 1 in perfect shape for $400 but I am curious of the depth. Yes I have asked the seller and he said 18" but I for some reason thought the 56" has always been 22" hence the search for an answer!

 

[Lookin4'67Galaxieconv]

I'm pretty sure the first series was 18".

 

[APS2000]

Series 1 and series 2, 56" box has always been 22" overall depth.

 

[Mr_B]

^
Correct the 56" and 72" was always 22"
I would want pay little less than 400 unless it like new and pretty much located on my doorstep.
Coupon sale price has been 650 on the 56" ...