Case is obviously different, and I would suspect so is the front drum. Most slant cars had 3 disk front clutch packs while V8 cars had 4-5 disks.
If it's free, I'd grab it as a parts tranny and break it down another day!
A lot of slant 904's had 4.2 kickdown levers, and a spare valvebody with part-throttle kickdown is never a bad thing to have. There are a lot of Jeep and other modern TF owners who wouldn't mind all metal servo parts...