The correct answer is 1966. There were no numbers on the helmets when Joe became HC. Numbers on helmets were a thing for a very short period of time.
Nicely done. I had forgotten that. No helmet numbers in '66. Numbers on the helmets from 1967-1974. Off again in '75. Stripes came off the pants around '68, I think?
I'm not a fan of numbers on helmets, as there are generally already 4 sets of numbers on the jerseys. (We get it... you're #14).
I like our plain helmets. The clean look is classic. Our home blue unis are as sharp as any in the country. I'd put the chipmunk on the hip, though.
I've noticed over the years that many teams now have plain pants, no stripes, maybe a small hip logo, and often white. PSU was a trend setter way back when!