Wow, great find! Take care of that beauty. The tank in that condition is worth what you paid for the bike.
Couple things:
The new battery might solve the turn signal flasher problem if it's happening at slower speeds. I use my turn signals to gauge the charge level of my battery.
Those "new" blued double walled pipes. My pipes did not blue after 25,000+ miles. At first I thought that maybe you had some single walled pipes and just needed to richen up the carbs some. That was until I saw the original pipe. Now I feel almost certain you are running lean, perhaps real lean. Just be careful and don't put many miles on it until you get it correctly tuned then do a plug chop at the different rpm ranges and read those plugs. You may still need to do the carbs. What size jets are you running? What is the needle clip position? Did you install a new air filter? Definitely check the valve clearance too.
Enjoy that bike!!