Hold on a sec, I remember reading something about this online before. I'll be right back.
Yes, I was right. Muslims are promised not only 72 virgins, or "houris", but alo 28 pre-pubescent boys. The exact numbers are unprovable as they're not mentioned in any texts, but supposedly those are the number Mohammed gave.
So yes, the verses you've given are about young boys. Take this famous poem by muslim poet Abu Nuwas:
O the joy of sodomy!
So now be sodomites, you Arabs.
Turn not away from it--
therein is wondrous pleasure.
Take some coy lad with kiss-curls
twisting on his temple
and ride as he stands like some gazelle
standing to her mate.
A lad whom all can see girt with sword
and belt not like your whore who has
to go veiled.
Make for smooth-faced boys and do your
very best to mount them, for women are
the mounts of the devils.
The meaning is quite clear. You might judge, but you have to remember that at that time, pederasty was still a widely accepted practice. Mohammed knew there were those who desired young boys, just as there were those who desired virgin girls, and so he promised them to his followers. Quite clever really. He knew that there were homosexual, and even pedophilic people out there, and worked to please them too.
However, I also remember reading (although I can't find the page where this was mentioned, grrr!) that boys were only to have sex with in heaven. As I said, I can't remember where it said this but I'm pretty sure it was somewhere in the scripture, something about how Allah wanted people to reproduce and that boys were only meant for the afterlife.
Sorry I can't help some more. I only wish I could remember where I read it. If it helps, I think it was something to do with muslims being rewarded in heaven with the 4 pleasures of virgin girls and boys (so sex), water, wine, and watching the evil burn in a fire or something. Grr, I wish I could remember. But yes, the verses you mention are about boys, though that does not mean muslims are any more likely to be pedofiles than anyone else.