The Saturn I-B second stage is the same as the Saturn V third stage (both are called the S IV-B) No commonality with the rest of both rockets, Booster engines on the S-IB were 8 H-1 Rocketdyne, the S-IVB was one Rocketdyne J-2. Saturn V boosters were five F-1, second stage were five J-2, third stage was one J-2.

I've got original Estes kits of both the Saturn IB and the Saturn V. still in their boxes. Found them online about ten years ago.