Bob
thats a completely new idea to me (what a great forum we have here) Just after i got the motor I employed a tech who didnt know his left from right, he installed a duo valve and mixed up all the pipes for example (so i fired him and decided to do all non engine stuff myself but not before he put a blower motor in for me) . Its quite possible he would have installed the blower wrongly. However I am surprised knowing MB that the design would allow it.

do you mean physically in the wrong way or electrically connected backwards?

is there anyway to check without pulling out the motor?

this is an interesting suggestion many thanks for your post
Keith