Yes, Now is the time when you will start to prep your hives for winter. If you wrap, you are probably ok to wait but I see no harm in wrapping earlier. Yes, mouse guards should go on now too. You will probably want to reduce the entrance before putting the guards up.
FWIW - I don't wrap my hives and have never wrapped my hives -so if you get to it late-its not a big deal.
As far as mice ( and mites) you will want to be proactive.
