The old trans 2466091 is 1964 A-body 6-cylinder (there are differences between '64 and '65 valve bodies to provide for '65 lever versus '64 button shifters; make sure you're not about to get crossed up by that).
The 2466119 was originally built with a 12¾" extension shaft and housing. So was the 2466091.
The '65 A904s built with the 18" extension shaft and housing were used in B- and C-bodies with 225 or 273 engine.
Either someone mix-matched parts when they put together that rebuilt transmission—the long and short extension shaft + housing interchange together—or this is actually a 2466118 (B/C-body with long extension) that was mis-stamped at the factory.