@Mike Self, yes, my car (74 tii, 2781801, it's in the FAQ directory) came from the factory with leather seats. The car came with service records dating back to 1976. Using the records, I was able to track down Tom Bass of Myerstown, PA. Bass was the former sales manager at Manheim BMW from 1972 to 1982 and was actually the person who sold the car to then second owner, a dentist in Lebanon, PA, Byron Clark, back in 1976. The sales receipt with Bass' signature was the first record in the stack.
In any case, Bass told me that the car was special ordered by the owner of Manheim BMW, HA Boyd. Boyd at that time was a BMW distributor servicing PA, MD, and DE. Bass said Boyd ordered the car for himself, picked it up from the factory, and then drove it around Germany for a month or so in lieu of using a rental, a practice he did more than once. When his vacation was over, Boyd had the car shipped back to PA and sold it at his dealership. The shipping invoice in my records shows the car was delivered directly to Boyd. Also in the records is an estimate of the car's value that Boyd generated for Clark at one point in time and it specifically mentions leather seats. The car also has a sunroof, AC, wooden shift knob, a passenger side mirror and came in black, so it seems to have come fully loaded and in a rare color as well.
Bass had some great stories. He said he got his start in 1968 selling Volkswagons and BMWs at Boyd's Volkswagon dealership in Lebanon, PA. Bass said one year (he thinks 1970), Boyd held out a free trip to Europe to any salesman that sold a dozen BMWs or more. Bass sold 15. Bass said Boyd took he and his wife Janet to Europe for five weeks, paid for everything. During his time working for Boyd, Bass recalled meeting Max Hoffman several times, including lunching with him and Boyd in Munich and going to Hoffman's house in Germany. Tom said he also saw Hoffman in New York City when Hoffman would host functions for BMW dealers and salespeople.
As you can see from the pictures I have attached, the leather seats are in pretty sad shape. My plan is to (eventually) buy new leather covers and seat pads and to put the seats back in the car.