Indicators

The 1972 brochure shows them on the Interstate but refers to indicators as 'optional' (They became standard for 1973). I've seen a suggestion that they were part of the Interstate 'pack' along with the Combat engine and the front disc but it almost certainly wasn't as simple as that.

The switchgear was there, but they didn't all have them is probably the only certainty. They wouldn't look 'wrong' on a '72...If you prefer them, then there is no reason not to fit them. They're quite handy at Commando speeds.

Of other road users haven't the foggiest idea what hand signals are,  so from a safety perspective they are worth adding to the bike. Just need to stretch your thumb to 9" long so that you can use the switch!

Regards, George. 

Even the dimmest V*lv* owner can probably work out what an outstretched right arm may mean, though I suspect that anything beyond that will be met with incomprehension (hands up all those who know how to indicate to a policeman on point duty that you wish to carry straight on), although they are still officially in use: https://assets.digital.cabinet-office.gov.uk/media/560aa58be5274a036c00001a/the-highway-code-signals-to-other-road-users.pdf.

The problem is that no one today is looking out for them …