Yes it's very close to the fuel tank, getting a bolt or 4 in there (properly) will be a bit of a headache too. Pull off the fuel pump lid and have a look under there to get an idea of what you're working with - I'll give you a hint, it's not very much at all.
In terms of drilling into the tank, yes it's a pretty real risk so be careful, or re-consider your need to mount it in that exact location.