It's quite likely that only Sinn Fein/IRA will decommission and they will only do a token amount to repair the PR damage done by the Colombian fiasco and to prevent themselves being returned to the US Register of Terrorist Organisations.
I doubt if Blair and Ahern will act together to see that it is done despite Blair's gung ho approach to dealing with those who subjected the USA to Black Tuesday.
Their information could have come from London or Dublin or could have been submitted jointly.