If it was sold in UK, they it will have a vin number. You will need to obtain a V5 logbook for it, which will mean it will need to be assigned a reg number. You will probably get an aged related plate or a Q plate. Then you need to put on:
working horn
Front headlight with pilot, main and high beam
tail and stop light.
It must have working brake switches front and back
It will need a chain guard
It will need to be quite enough to pass the mot- which is up the the mot'er, if he thinks its too loud of not ( as its pre 1983- unless DVLA asign it as first regfistered after 1983)
You dont need inticators on it if its given an age related plate
Another thing to concider is that the alternator may not be capable of runing the engine and lighting too.