They will still be able to smell eachother and it might aggravate them both, as they are both unneutered.
I am in the process of bonding my two males, and they live in a converted shed with a thick wire division, and have both been neutered and known eachther for years. They spend most of their time licking one another through the bars. I can't quite trust them together yet because of the dominance thing they have (humping, leading to nipping and chasing occasionally) but I know they love to be together, which is why I have them living together, but safely. They have never once nipped or scratched through the partition in the years they have lived together, and I am positive they won't, otherwise they wouldn't be housed like that. In the end it is for their happiness.
However, if your two little buds don't really want to be around eachother, I wouldn't house them sooooo close. If you need to, definately get them both neutered, and this should help.
Jen