There is a correct index position for the Cessna 150 propeller. Fig 14-1 page 14-3 also para 14-6 page 14-2 of the 100 series maintenance manual.
I stand corrected, this is specified for the C150, (Section 13 of the newer manual). Happily, I have checked, and mine is correct, and has been all these years. It just goes to show that the tribal knowledge [I was taught] was incomplete!