I'm going to suspend my belief until I see something directly from WotC on this.
However, if this is true, I find it quite encouraging, even if Unearthed Arcana probably isn't in the top 10 1e products I'd love to see reprinted, this and the 3.5e reprints show that this isn't a one-time thing.
I've long thought that WotC's (and TSR's before them) notion of competing with itself via old editions was something of a self-fulfilling prophesy, and that through smarter marketing they could have done a much better job serving a broader spectrum of the greater D&D fan base by synergizing older products with newer releases. Like a $5 .pdf of the original Fiend Folio released a couple months before the new "Fiend Folio" comes out, or a free conversion guide to edition x downloadable with code typed in from back of new product. That type of thing.
Computer game companies do this type of thing all the time. Nintendo, for example has a rewards program where, when you buy a new product, you get "coins" you can use to download their old classic Mario and Zelda games. Seems like WotC could do a similar thing, and there's no reason why it couldn't work the other way... Buy $x worth of old .pdf's, get a redeemable credit for new version game. Get the fans of old editions who have shown a proven willingness to give you their money to try your game at a reduced price.
It's all about getting the committed gamer to come through your front door. After that, if you have a good product, it will sell.
I also think WotC's marketing should be selling their new edition buy saying, "This new product will help make your D&D game better," rather than saying, "This new version of D&D is better than your old D&D game." And then focus on making products that as many D&D gamers will find useful to their existing games as possible. Maybe that's a subtle difference, but I think it's a vital one that has caused a lot of hurt feelings over the decades.
I guess to swing this back to the original topic, I think it'd be a good idea for WotC to look at products to re-print that would be useful for all D&D players regardless of edition. I think the 1e DMG certainly filled the criterion. The 1980 World of Greyhawk folio would probably be next at the top of the list.