Combining playthroughs

[elpoko]

This is a bit of a stupid question and I think I already know the answer but it would be great if someome could confirm either way.

I have my Hard Bastard/ no deaths run complete and I'm halfway through my unarmed playthrough which leaves firearms only, indirect only, devices only and indirects only.

My question is if I complete another run (with no active restrictions) without using any firearms, devices or indirects, create a backup just before completing the game then reload that save completing the game after killing an enemy with a firearm will that trophy pop or does the firearms restriction have to be active?

I think my answer is in the trophy description but I'd like one more playthrough instead of three if possible.

I hope my question makes sense and thanks in advance to anyone that answers.

[Sydoki]

@elpoko hi, did you ever end up finding out if it's possible to stack multiple playthroughs?