The idea that Americans would ever use their right to bear arms to stand up to tyranny is a myth anyway. Where were these so-called patriots during Japanese internment? During Jim Crow?
Given the nature of fascism, it's far more likely that gun nuts would be cheering on the government during such a scenario.
This is a brainlet take.
If the working class had been permitted to be properly armed in their capacity as a vanguard for the organized union strikers, etc., then several of the already pretty widespread number of labor uprisings against capital or the United States government might have been successful. Take, for example, the Battle of Blair Mountain or Coxey's Army. The colored also exercised their right to bear arms to defend their suffrage in the face of Reconstruction being undone; (this right was of course later denied.)
Anyway, let the gun nuts cheer on the government if they want - although you won't find any of them taking up arms for Biden - but Labor would certainly find itself in a better position to negotiate, if fully armed.
I reject your premise that we can unite “labor”.