Yes, wraith, it is. In random battles, you can select it to match you by skill level, or to select an opponent completely at random. Then it matches you up, and it randomizes the map conditions. As far as I can tell, the turn timer is always between one and two minutes, but the map is a random one from the core 2p map list, I believe. All balanced, but some of them are dumb. Also, I have yet to run into any weather conditions or fog of war in random.
You can also make custom maps and submit them, much like it's supposed to be for Brawl, but the ones that you can submit to the service are limited to 10x10, which sucks. You can choose to download a random map, or a recommended one, and after you play it you can rate it 1-5. So far, three of the four random maps I've tried have been jokes, and I rated them 1s, and 10x10 doesn't leave a whole lot of room for creativity. Luckily, with friends you can trade and play any map, and the design room lets you go up to 30x30, which is plenty. One thing I wish they had was the ability to trade your custom maps from Advance Wars DS to the new game, because porting them will take a long time and lots of patience.
Also: If you wish to see the awesome that is Advance Wars, see
this old post of mine. Don't read it all if you're sane.