"IIRC Smithwick later states that McCluskey was killed in a brawl."

Yes he did! Remember not much nice things he had to say about the guy.

Founder
Ancient Order of the 1895 Winchester

"Come, shall we go and kill us venison?
And yet it irks me the poor dappled fools,
Being native burghers of this desert city,
Should in their own confines with forked heads
Have their round haunches gored."

WS