Thanks for your replies, everyone. I am defining the "bushing/sleeve" as the large roll-pin that presses through the rear mounting ear. I define the "spacer" as the larger cylinder that just spaces and won't fit through the mounting hole...

It sounds like the longer bushing the alternator came with must have been a convenience but not technically "correct" as it eliminates the bushing+ spacer. So going from the head out - short spacer, short bushing (in rear ear), long spacer, bracket, front ear. Right?