Well, strip my gears and call me shiftless....
I never noticed it was different on each end. It's not going to make a difference in how long it lasts or how strong it is. I'm guessing the different taper is there maybe for clearance reasons. My original '69 drive shaft is about 80 miles away right now, otherwise I'd go check it for you. (It still has the tranny yoke attached so I'd be able to tell). If'n it were me, I'd mock it up both ways and see if one way seems to make "more sense" than the other.