71 fan shroud

[arkansas]

Hey guys,
I'm new to the forum, but I've been playing with these trucks for a few years. I've got a question for some experts. I have a 71 1/2 ton with a 250 and factory installed T350 tranny. My dad bought the truck in 73 with 18000 miles on it. The question is, the fan shroud that was on it was the plastic v8 style that fully surrounds the fan instead of the small top shield that I seem to see in all the 6 cyl. pics. Anyone ever see a v8 type shroud on a 6cyl truck? With very little previous owner history and the core support obviously not having had anything previously bolted on, I would amazed if someone had changed anything out before my dad got it. I'm working very slowly on a restoration and am trying to figure out some of the odd things I've found on this.