273 valvetrain question

It had the flat top 2bbl pistons. At some point I'm guessing either the original motor blew up or rebuilt it a long while back and couldn't get (or afford) the domed pistons. It has the valve covers and air cleaner for the commando, weird that someone would go to the trouble to make it look like one if its not. No idea what converter is in it. That may be helpful to figure out while it is out.