The debate concerning the 2nd Amendment did not mention Lexington and Concord.
The closest comment in the debate that would suggest as such was this one,
"Whenever government mean to invade the rights and liberties of the people, they always attempt to destroy the militia, in order to raise an army upon their ruins. This was actually done by Great Britain at the commencement of the late revolution. "
- The Congressional Register, 17 August 1789 - Mr. Gerry -
Even there, it was not specified. However in retrospect, it
could be inferred I suppose and not every word makes the register. It's more like "minutes" of a meeting.
There was quite a bit of debate about the militia, a LOT, about those with religious scruples being exempted from bearing arms in the militia.
An early iteration of the amendment gives a pretty clear picture of what was intended:
"
A well regulated militia, composed of the body of the people, being the best security of a free State, the right of the people to keep and bear arms shall not be infringed, but no person religiously scrupulous shall be compelled to bear arms."
At one point, the words 'in person' were added after the word 'arms' at the end, thus allowing religious objectors to serve in the militia by proxy. This was removed because, those who would object on religious grounds would also likely object of someone serving in their place as well.
Here are the discussions, with the various re-phrasing the took place -linkage-
There's enough here to provide fodder for all sides of the discussion.
