hold on there! 1) no criminal record has come to light yet - all is known is he spent some time on remand, which is hardly unusual for a young black man from Tottenham. The rest is rumours and accusations. Anyone can give an 'account', incuding the met who are in the habit of smearing their victims (such as De Menezes) via anonymous brioefings to reporters - it's proof that matters, and that ain't there yet.
2) a firearm was found 'at the scene' - the IPCC have not yet confirmed it was his, the cabbie's (yes, this happens) or the other passenger, or even a police plant (equally a known phenomenon). It hasn't been established that it was on his person
3) his best mate was murdered earlier this year - there is every chance that, if he was carrying the gun, it was for protection. I know this area, and IMO that don't make him a criminal - just scared.
4) What is KNOWN is that he was the dad in a long-term stable family unit. The point being, that means stability etc.
in other words, you're jumping the gun a tad (sorry, no pun intended). Given that these police fuckups have a history of being followed by a lot of lies from the Met, and they've ALREADY been caught on one lie(duggan didn't fire at them), it's best to wait for the full IPCC report
did his gun have a licence then?