Yes, they are a request, with no guarantee.
However, I'm not sure your kids would be comfortable in the bunk beds, anyway. They are kid sized-- shorter than standard bunk beds. I think they're rated to 100 pounds for each bunk, something like that. My dds 13 and 10 would not have been able to stretch full length on them, but they both sleep curled up anyway, so it was ok.
You might be able to also request the 2 queens and a daybed, which would probably be a better option for you.
Be sure and call guest services a few weeks before you go, and request a free upgrade-- be very nice and polite and excited about your trip, and ask if they could put in a request for a free upgrade for you. They will note it on the computer, and will try to honor your request if at all possible when they block out the rooms-- usually a week or two before your stay. Again, of course, no guarantees, but if you request it, it's in the computer. For a 2 queen and a daybed room, that would probably mean a better view room as an upgrade.
HTH!