Best wiring diagram for 75 k10? mfr date help?

[bilede]

Son and I are trying to resurect a 1975 chev k10 from the dead and need wiring assistance but can't seem to find the correct wiring diagrams. factory manual says if manufactured before 3/1/75 get 74 book, after get 75. I don't have any idea when its was manufactured as door sticker is gone. was first registered with state in 5/75 so could be either way. Vin sequence is S153160 in case that would help.

thanks!