what ever you do, dont fibreglass the holes,
weld is the way to go.
fibreglass, will look good for abit, but as times come it will sink, my boot holes have been filled but have sunk because of the fibreglass..
pay a little extra for the weld, and you will get a better boot that wont sink or crack (meaning you will have to paint the whole boot again when they patch it up again).
my 2c, I've learnt my lesson.