Of the 2 hand interpretations of the clock, March 7th would mean Forza is releasing early, 2 weeks before it's Spring release window starts, while July 15th would mean that it got delayed out of it's Q2 Spring window into Q3. I'd rather have an early launch than a late one, and AAA releases almost always avoid July so I doubt Xbox would have went that route, so I think it is probably a March release, but we shall see.
It's also possible that the hands aren't meant for exact date but rather a general date range, what are the chances that Twitter's stopwatch emote just happened to have the hands in the exact right position for what he needed to convey about the date? Maybe we're not meant to interpret both hands, but only 1 of the 2, which would of course increase the chances of the stopwatch emote being a fit for what he intended? Maybe he is just giving a generic March or July release window?