Well no one told me grannies were easy, I just figured they were so slow already they would be pretty easy to pick up at a care home?! They don't need all kind of special tools just 2 different jaw pullers to get by on. Also a simple press from harbor freight does it just fine, seen it...
You can pretty much go to any person who works on transmissions, rebuilding is easy for them, upgrading is just as easy for them. What goes into the transmission are not extra parts, just beefed up components that are already present. Send out your gears to a tranny specialist and have them...
Your right there are some minor differences, mainly the casting shape is slightly off on the valve side. IDK that is a bit weird, you should have asked for a part number first and asked for the engraving.