To my knowledge the 10 pin headlight switches were only on early cars, to -71 or -72.
Every 73+ car I have pulled the switches out of have a 11 pin headlight switch.

Can you use an early switch in a later car? Can you use the later switch in an early car?

I looked at the '74 diagrams on Pelican, and by my count only 9 wires go into the switch. (Hard to tell for sure because the switch is on a page boundary.)