Calling that a tank is blasphemy!!!!!!!!
I would call it armor but not a tank, that's funny.
I think any vehicle with a mounted gun/weapon system would be defined as armor. The difference would be soft skinned or true armor and certain countries define their weapon systems differently. Even the SPH had a thin armor as did the M113 and kind of fall between what I would call soft and hard armor. It's not only the thickness of the armor but the mission it's designed for that defines what it is. Like I would definitely call Vietnam Gun Trucks armor.
To me a Tank is a vehicle designed to fight against other tanks, kind of like a heavy weight boxer fighting another one, not a middle weight. Which is different then a tank killer or anti tank vehicle, them being more like a middle weight or even lighter in the case of a Mutt with a M40 106mm RR or later with TOW.
IMO put a GPMG on a Jeep and it's armor, it now becomes a combat vehicle. So in essence a combat vehicle is armor whether it's a Humvee or M-88. Maybe I think that way because I was Cav when I was in the Army.
Mike you saw a M108 on ebay for $55 and didn't email me!!!!!!!........ I think that one started off at $55 and ended up at $100.