Looks like a SuperSport to me also, but later than 66. I have a 66 with a July 66 serial # and it has downtube shifters(brazed on posts on downtube) also had bolted on kickstand(no welded on base). unless I'm misremembering mine also has Huret rear dropouts with axle adjusting screws. Mine also came with track drop bars and an Italian stem, which I've seen on a few other SS. May have been an option avail in some shops, looks cool, but I found there's nowhere to mount brake levers that works well. Don
edit: forgot to mention mine has the original Brooks B15 saddle as did the 71 model which I had for a while before passing it to a kid in our church.