Well, the first thing this points out to me is you are more observant and definitely know more about Oliver tractors than I do.  Thanks again for the help.  The front hitch would definitely make sense to me, I've had a couple pickups with front hitches and it is a lot easier to move a trailer that way, especially a boat trailer.  The only thing I can think of for the belt pulley is if they might have had a big generator that ran from a belt for use away from the usual power supples. I have seen those generators at military surplus outlets but don't know the vintage, etc.  It would seem logical though, that an airport tractor with a PTO would also have the belt pully for supplying power anyway they needed it.  

Thanks again for the help.