I bought one of those new from Heron Suzuki in 1976 I think it was , if I remember correctly it was about £500 which was quite a chunk of my apprenticeship wages back in the day, only problem i had with it was the pointless ignition box packed in just after the warranty ran out and it wasn't cheap to replace because it was a sealed unit , always the way ain't it.
your bike looks exactly like I remember mine being, I think it used to eat tail light bulbs too, but the XS650B Yamaha I got after that did as well so it might just have been dodgy bulbs back then.
I look forward to seeing a photo of the bike in a nice location when you have it finished.
Colin.