'70 Swinger Project

So I have this... Thought I'd be able to figure out how to interpret it, but all the online tools I'm finding doesn't show the codes the same way - for instance, I know from the VIN that it originally had a 225 with a 1 bbl carb. So in theory, the carb code on the build sheet should be either E24 or E25 - yet it looks to be 12 on the build sheet.
Specifically, I'm looking to see what the original transmission was Base on what I've found so far, It should have been either a 727 or a 904. Any thoughts out thereBuild sheet.jpeg ?