Exhaust leak

Hi all,
hope someone can shed some light here...
Mr Mechanic just replaced my cracked exhaust manifold with a good one. Everything was done by the book (shop manual). No leaks between manifolds and head but a bad one in the heat riser area, between intake and exhaust manifolds. The mating surfaces were checked and straight, new metal gasket used and bolts tightened (15 lb.ft as the book says). BUT one of the three bolts had to be loosened and re-tightened once as he/we forgot to reinstall the starter cable bracket under the bolt. Could this be the cause?
Further, is there any way to slide a new gasket (if needed) in between the manifolds without removing the whole assembly again? Any sealer recommended or is the metal gasket enough?

Thanks a million,
Tina