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Just for future clarity, your 79 has a generator and takes a regulator only. 78 was the last year of the old Bosch electro-mechanical regulators (coils and moving points etc inside it). 79 used a solid state regulator (no rectifier) like the finned one in the pic above. So different part number and whole different look from the up-to-78 regulator.
Later bikes (1981 Ironhead from memory) with an alternator inside the primary used a solid state regulator/rectifier that looks much the same but functions differently to change the AC alternator output to DC.
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