Nice cab. Please tell me you have another, as that would sound great with a plexi!
I've also noticed US prices for cabs seem to be higher than the UK/Europe (although that perception may be skewed by crazy asking prices) - more so than the heads. The question is whether the shipping costs would justify the difference to a buyer.
My similar era 1935A has faded cloth such that it is almost ‘cane’ colour and the levant has a distinct faded to green colour. Great cab and I really like the T1511 speakers.
If I were a buyer I would want to know why the top two speakers have been removed/rotated and that the cones are in good condition and original with no odd noises. As a players cab the missing magnet covers will not be too much of an issue. Pics of the castor tubes, whether the bottom has been hacked about for odd wheels would be good, most of them have lost their bottom cloth.
Address those questions and someone might be able to give you an indication of price on open market.
The 55hz T1511's don't go for as much as the T1221 75hz, but still desirable. Assuming the speakers all have original cones, original cloth/tolex/casters, you'll be in the $2500-3000 USD price range, possibly more to the right buyer.