You said they are due the 22 and 24th. They are 3 months now? They were bred the end of June, first of July? 3 months, 3 weeks, 3 days and 3 in the morning is the old saying around here. They should be rounding out some by now and should start to have the udders showing a bit within the next week or so. They won't get alot of udder until a week or less most of the time, but it should be getting obvious they are pregnant. The belly drops a little and they will look like they are waddling a bit. Ist time gilts aren't as big as sows, but usually show a little udder sooner as it develops. Sows will look a little more drop belly but often won't udder up until real close as the glands are already developed but "dormant" so to speak.
With a pen that big, with the boar out, you could just wait and see if they decide to go to separate ends; but if one starts and the other is hanging around, you need to have a plan to split the pen so they can have and bond with their own babies. Is there a shelter for each or is it inside? They need for the babies to have a draft free spot and that means huts or something if they are outside. No sawdust for the first few days at least, it will get in their eyes and mouth and suffocate them before they can get to the udder. Use straw or fairly decent old hay that is not weedy. The sows don't clean them like cows or sheep or goats or anything. They are born, wiggle out of the sack, and crawl around to the udder. The sow will expel the placenta when she is done with each "side" or horn of the uterus. They normally deliver one side then the other, seldom do the 2 come at the same time. Sometimes they get up and eat it, sometimes not; I usually take it out so the little pigs don't get "lost" in it.
Some sows will let you stay close and some will not want you anywhere near. Don't interfere but make sure the pigs get around to the udder and don't get lost crawling away as they sometimes will. Nature performs miracles, but a new sow can be clueless about what TO do, and NOT to do. If she gets up and down or if the pigs get to squealing at all, they can get stepped on, laid on , or she can go after you. I advise not being in the pen and that is a good reason to have them penned so that you can be outside the protection and still close enough to help if need be.