Hi guineapiglet is right that I have 2 boars (Rescue brothers) but they were a year old when I got them- so although we missed the cute baby pig stage , we thankfully by-passed the arsey teenage stage.
Though now at 2 yo mine still throw the odd Kevin-esque strop.
Boars are lovely and alot of people say they are more affectionate than sows.
I think that depends on the pigs TBH.
You'll need to consider:
They'll get The Teens. But there's things you can do to minimise.
They need room. Lots of it.
Mine are in at night in a 4'x2' cage. I give them each a box with a newspaper and fleece.They like their 'own' space when they need it.
Though last night I gave them a box full of naice hay (fancy carrot and camomile stuff, not just bedding hay) DD said they were in together. I heard nothing from them last night. I put them in the small bedroom with a duvet on the top for peace.
That's just their sleepbed.
In the day they've got their Pighouse.
Lots to occupy them. Boxes, tunnels, masses of hay. If they've got somewhere to go, when they have a barney, one doesn't bully the other.
And the amount of waste these critters emit beggars belief 
But that's a direct result of the all important FOOD! A guinea-pigs reason for living.
Which is nice because they are very bribable.
I've put a little oil filled radiator in their Pighouse. Get a thermometer too.
I like their Pighouse temp to be 12-16 c. They're completely sheltered and have their hay.
They don't like draughts or damp, but can cope with cold to a degree. (I put the heater on before mine go out.They aren't too hot indoors. Constant temp is best)
Ask the owners:
which is the bossy one (they might try and change this though if one gets a bit more cheeky and decides they want to overthrow the other)
any health problems?
Have they wormed them (probably not if they don't go on grass)
Any signs of mites (bald spots, snapped off fur, scratching?)
Any food make them sneeze (,y little pig sneezes after ReadiGrass. My GP1 gets a clear nose discharge after fresh grass. Both been checked at vet by Rodentologist)
Find a good cavy savvy vet - you probably/hopefully won't ever have to take them. But if you need a vet, you'll need one quickly.
Read up on impaction (stuck pooh in boars bottoms)
And boars' willies- they can get stuck out (especially if they try it on with each other). Not that my chaps ever would
They sound lovely.
We will need photos you understand!