If you're in/near Collier or Lee county RUN, don't walk and grab that Sirrus listed above. Granted, it's not the bargain you got, but as said, if it has clinchers, then you have two bikes between which you can swap wheels.
I don't remember the exact details, but don't try to put any other brand of handlebar, especially a flat bar, on that Cinelli stem. It's a slightly different clamp diameter, and the stem won't ever clamp down tightly on another bar, and you can damage the stem trying to get it to do so (not that I would know first-hand or anything....cough....cough....). In fact, if you're really fixed on switching to a flat bar, I would remove the bar/stem together, with the brake levers and cables in place, so you can sell that as an assembly. You would need flat-bar brake levers anyway.
That said, I would seriously think twice about running a flat bar with downtube shifters. My wife tried that for a while, and didn't like that reach. She went back to drop bars. That Sirrus in Ft Myers is set up that way; if you buy it, you could use that as your "test dummy" for such a setup.
And joining the chorus - don't repaint it.