The special would have come off the line between December 1950 and end of the run. During at least part of that time the (dent) in the firewall would be present allowing a dealer to slip in the old type chassis. I also see there is an AC replacement element oil filter unit on the car rather than Fram or purolator. It was common to change from the 1/2 type especially in the late 70's & early 80's when production of the version ended by the filter makers.
I am reminder of a car that an early member had in Fon Du Lac. It was black with the dealer installable wide stainless (yes K-F for a time offered the Deluxe belt molding as a dealer installed accessory for the Specials). It still had its original spare tire the last time I saw it.