CIS in 1977 didn't have a computer in those days. It was just a pressure-based system. I would say those plugs on your '77 engine harness are probably for the ignition coil and maybe a rollover switch on the fuel meter (shuts the fuel pump off if the car rolls over). The best thing to do is look get wiring diagrams from each car.
http://forums.pelicanparts.com/porsche-911-technical-forum/74634-wiring-diagrams-1977-911-a.html
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'66 11-window VW Bus (Fuel-injecter'd Super-1600, IRS, disk brakes, MB CLK rims)
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