Thanks for the photo Kevin. It really helps to understand what will need to be done.
Thanks for the tip Evan. This one's going to be bone stock and it will likely get driven off the pavement some so it'll get the factory style mounts.
My Grandpa bought the truck in 1953 and it was well used for his plumbing and garage businesses. The cab is really rusty in the cowl. He even pop riveted reinforcements between the fenders and the cab to keep it together as shown in the attached photo. I'm still torn if I should switch the entire cab or use the new one to repair his cab. It would be a lot of extra work to fix it but at least most of it would be the cab he sat in. If I replace too many parts, it seems like it wouldn't really be his truck anymore and reminds me of this story:
Bill was admiring the axe John was using. John proudly told Bill "This was my Grandpa's axe." Bill was surprised and said "Really?? It looks like it was hardly used!" John explained as his Grandpa got older, and it was getting difficult for him to swing it anymore, he gave it to John's father. The same thing happened when he became elderly and passed it to John. John said "By the time I got it, it had been filed down so much it didn't work well anymore so I replaced the head. My aim has never been very good and the first time I tried it with the new head, I overshot the wood and broke the handle. So I replaced it with a new one." Bill said "Well hat explains a lot." John finished by saying "Yep, I sure am proud to have my "Grandpa's" axe!"