See if this link can help as it has good info on frame & engine numbers and paint colors:
http://www.spookytoms.com/CB750K-IDPlates.htmlA couple of thoughts here ...
Is it possible your frame tag reads 11/74 and not 1/74?
Can you check/confirm your engine numbers to the link above?
Can you check/confirm the serial numbers that is stamped into the frame neck opposite side of the frame tag.
Your front turn signals are the '74 and earlier type as the '75 and later were larger.
Looks like your paint is the original '75 Flake Apricot Red.