In the early 90's I picked up and Alpa 9d with 50mm 1.9 and a German 135mm at a yard sale for $75.

And at an estate sale last year I bought a Bronica ETRS, AE-II finder and with 50, 75 and 150 (4.0) MC lenses for $300. All but the 75 could reasonably be called "like new." And the wide and tele sported the proper lens hoods. All in good working order.
Question -- what is the difference between the 150 4.0 and the 3.5?