Is it possible to obtain Tenpenny security armor after the ghouls move in and have killed all residents?
I forgot about stealing one of these before doing the quest and now my collection is imperfect and it's
bugging me Is there some way to still obtain it? I would prefer not to have to use console commands,
but I will if I have to, I don't want to replay 10 or so hours... Thanks in advance!

The bodies of the guards should still be there to loot.

I think they are only there for the first 72 hours, whether that is after the Ghouls move in or the last time you went in there I am not sure.

Then I guess I'm screwed... It's really killing me (gaming OCD) as I wanted every armor I could get and don't want to reply 15-20 hours...
But I don't want to use console commands either, so I guess it's too bad... Thanks anyway!

EDIT: Actually they were never in the basemant at all, just blood. I could comment on bodies being there, though.

I think you could get away with a console command in the case of lost chance at the item in question, I do not think it would be a big deal. Heck leave money behind at one of the merchants to make it fair:D