ATC SCM50ASL Pro vs ATC SCM 50ASLT

Oh come on it’s just a cabinet; there’s no voodoo to the ATC cabs - I’m just saying if they find the Pros ugly (I don’t - I got the 20 pros rather than the 19s, though yeah, they're not lookers), they could swap all the internals for a beautiful new cabinet. Replicate the bracing, lining, stuffing, vent, amp cutout, done. Of course, the 100s have more bass, but they’re bigger, more expensive, and the Pros will look as ugly to them as the 50 Pros.

Oh come on it’s just a cabinet; there’s no voodoo to the ATC cabs

No voodoo for sure, since that isn't the ATC way.
However any deviation from how ATC does its cabinets will result in different sound - why reinvent the wheel with the possible compromises?
If saving money and 'shiny' cabinet is required I wouldn't cannibalise a genuine ATC to do it, just saying.
Get the Pros or the Domestic version or purchase/build something else if they aren't to ones taste or budget.    

I do not find the the ATC PROs ugly, I’ve owned Merlin monitors in black rough and it was fine.  My original post simply asked for confirmation and/or insight into my understanding of the identical nature and performance of the two ATC products.

No veneering will take place.  Thank you.

There is a difference between the pro model and the domestic model. While both of them are 50L cabinets, typically ATC suggests the monitor model if the room dimensions are relatively small. The floorstand version sounds a bit larger/bloomier hence it can overwhelm more easily in less than 250sqft room. My guess is it is due to the way bass builds up when speakers are on the floor. The monitor version when lifted on stands sounds a bit more compact and may be a shade dryer. Recently my cousin was in a similar dillema while deciding between active studio SCM100 vs active Floorstanding SCM 100. We asked it to ATC and their suggestion is as above. My cousin picked the studio version finally since room was just about adequate in size.

I didn't know that. The internal chamber volume for the bass driver should be the same, so the difference you mention would be down to acoustic reflections from an open stand vs an elongated baffle, sides and rear; perhaps room gain depending on proximity to room corners.

P.S. Sound Anchors are still some of the best stands out there; not cheap but then again "mini-stands" for the 50 cab shouldn't be as expensive in terms of materials as for a small bookshelf.