New 360 & a couple of questions

Old gas that has been in an unsealed container, just gets harder and harder to fire up, as all the Volatile elements have evaporated. But once running it makes no nevermind at no load.
If it was kept in a sealed container out of the sun, then it will be fine.
But for cam break-in, you cannot afford to be cranking and hoping for the best; the engine needs to fire up right away, and immediately be brought up to break-in rpm. So, at the least, the gas in the bowls needs to be fresh from the pump. The engine will start on that, and run on that for at least 20 to 30 seconds while it is being polluted with the gas from the tank. By that time, the engine has long been up to speed, and you have checked for fuel leaks, and even pulled in the timing.
Best of luck to you.