A certain amount of glue squeeze out is to be expected, and I know of at least one luthier who leaves a bit just to let people know it's really hide glue. It doesn't hurt anything. Chisel marks in the top can be a problem as they can be 'stress risers'; places where cracks will start, if they're big enough. AS has been said, the old boys tended to work quickly, and didn't worry too much about cosmetic issues. They usually got the structural stuff right, though, as far as I can see, and as for acoustics, that's in the ear of the beholder. Even old instruments that are pretty fancy on the outside can be quite rough where you can't see them.