Fiberglass patch kit

[J-440]

Evening all. I have just finished installing my glass fenders (already painted) and some of the gaps are a little too wide. The body shop that painted my car did so...but painted the fenders separately. Yeah, backasswards I know. It's a long story. Anyway, I was wondering if there was a patch/gap fill kit that I could do myself. Instead of taking the car back up to a different shop and paying the big bucks. It's 2014, don't tell me no one's come up with an idea like this. Thanks again.