Neutral safety switch harness question specific to 1974

I'm thinking with the seatbelt interlock system, they interrupted the start (yellow) in the chime box as well as neutral safety right here and never had a brown go to the starter relay. They just interrupted the start circuit in the chime box and took care of disabling start there.....
Possibly there is a starter relay out there that only has terminals for 12+v, yellow start and solenoid??
Or is that frigging crazy?