Would this plane have flown?

My guess is yes - but seriously out of trim for sure. I'd do an empty
trip around the pattern for evaluation. Assuming the handling is
tolerable, load up but keep the speed down.

This is a case where it is really not correct to simply rely on an A&P
mechanic for such a decision. The training they receive doesn't really
include the consequences of aerodynamic variences although their
experience may be very valuable. It really is a situation where the
judgements and experiences of other pilots etc is as valid as any A&P
could give. I definitely don't want to put A&Ps down, but they don't
walk on water - they are only human in their ability to evaluate.