As long as "when the project is done" is a reasonable length of time (ie. weeks or months, not years) then I'd say you're not quacking like an employee.
I don't think working efficiently and smartly is a good criterion for judging whether or not you quack like an employee.
Well given the standard of perm workers I've been around lately... it seems to be a different mindset and good contractors seem more aware they're there to get the job done.
YMMV of course. And yes, I tend to find six months is a good timespan, project dependent of course. I know there are contractors who hang around at places for years, that seems like something different.
I don't think working efficiently and smartly is a good criterion for judging whether or not you quack like an employee.