Nice looker. Just a few observations, not meant to be critical, just informational. The front stay for the front mudguard is missing. I wonder what size that front tire is? Original is 3.00 or 3.10-19, if it's larger, it's got a later front mudguard because nothing larger will fit under the original mudguard. The petcocks have been replaced, not unusual. It looks like the spring to the centre stand is loose. The seat is correct for a 69/70 Roadster/S type/R type, less the strap, not unusual that they were cut off. What is that round thing on the end of the right handle bar? Maybe a bar end mirror mount? I'd be interested to know the production date/number on the plate on the headstock behind the headlamp shell. I'm pretty sure those years had silver barrels too so it may have been painted. The rear tail light faring should be silver flake, not red. There should be reflectors mounted under the front tank mounting studs on L brackets. But no doubt it's a good looking version for it's age. Doesn't look like it would take much to get it in running order if it's sound.
Welcome and good luck/good riding with it. Get new Amal Premiers or re-sleeve and rebuild the carbs, it will be happier. The original style carbs were good but the slides wear fast, aftermarket will give you headaches, one way or the other. If the engine hasn't been rebuilt, it will need all new seals and most likely bearings. Major job. Check the swing arm for excess play left to right by pressing on the rear of the rear wheel. If the swing arm shaft hasn't been modified for excess play, that's a necessity. Probably needs a new headsteady arrangement, not a big issue. The 72 version and up is adequate.
I'd like to see the other side.