Yes, I noticed that the Mark II SARC with the moderate changes, suggesting that it had merely lost its turret in lieu of mounting the 20mm Breda, has a higher
serial number, F.22888, than the Mark II car with, seemingly, a brand new hull, F.22753 or F.22853. Note that the lower photo is of a model
of the Mark II with the Breda 20mm, so the serial number could be spurious (though most of these model makers pride themselves on reproducing actual vehicles and weapons, replete with correct serial numbers). The other thing is that the lower vehicle---and I've seen actual photos---does NOT show the front driver's door welded shut, which would be impossible to hide, but rather no access/exit door adjacent to the driver and a newly positioned door midway along the hull, suggesting a newly built hull.
Of course the disparity in the order of the serial numbers needs to be explained.