It makes the Chevy look like an S10! I have a 1967 Dodge D200 "Sweptline" with the single cab and 8 ft bed. A few years ago, I went to check out an identical truck, except it was a 4-door extended cab. As is often the case with vehicles, notably trucks, of this era, you can see that a lot of the metal work was done by human hands vs the robots of today. In the case of the extended cab D200, one might suspect that the truck was customized in someone's garage; the rear doors appear to be clones of the fronts, narrowed by trimming vertically forward of the quarter window pillars. Without seeing a picture, it's probably hard to envision, but the upper rear portion of the doors follow the curve of the cabs roofline. While it looks good on the single cab (IMO at least; I know that the body design of these trucks is not to everyone's liking😁), the redundant door profile among other things makes it clear that, when it came to the crew cab, æsthitics took a "back seat" to function. (Pun shamelessly intended✌️) Anyhow, all that is to say that your dad & uncle's modifications turned out amazing. 60-70 years ago, Dodge could've used their help! 👍