I did this too (on both legs too) was like they forgot to use metal on these and made it out of butter. I've done similar things when working on cars, it can be so frustrating but usually drilling them out is a last resort that I've not had to do.
anyway, back to the jag-stang. What i did was get the next size up allen key (if you have a set - cheap enough from home depot / B&Q) and use that, you may have to tap it in but should just fit.
good luck and don't panick!
