I take it that the boys are quite young?
Littermates generally get on well but guinea pigs are very individual and they don't read any rule books. If they do start to squabble then it can be anytime between 5 months and 12 months old (again generally speaking).
The squabbling may just be an odd rumble or it may be very territorial and lead to blocking sleeping quarters/food bowls/drink bottles. It can also move on to physical fighting. But this isn't always the case so please don't worry, just enjoy them.
The best I can advise you is to get to know your piggies really well, their behaviour patterns etc , as any changes in this need to be monitored. The other advice is to give them plenty of hutch space, as much as you possibly can, plenty of floor time too and two houses, water bottles, food bowls.
Pigs will often fall out over resources (shelter, water, food) if they don't have to compete it lessens the risk of squabbles.
Please remember though that there are lots and lots of people who have pairs of boys and never have any problems with them throughout their lives. If you provide stimulation and space you'll increase your chances of having a successful pair too.
Enjoy your piggies x
PS In my experience, neutering is not an answer to fighting, it doesn't alter their behaviour and is an unnecessary risk.