just to pick a nit....
If I recall correctly, not all Cessna 150 spinners had screws securing the forward bulkhead.
On some spinners the forward bulkhead (p/n: 0450027-10) was plastic. It was wedged/glued into the spinner, and it was a snug fit into the center hole of the prop. It was not screwed to the prop like most spinner forward bulkheads. So those 150s so equipped would have just a single row of screws at the aft (wide) end of the spinner.
I have that style on Snoopy (1976 C-150M)