Gatordev, as much as they are drawing down 4th MAW, I'd be surprised if they are so hard up for reserve helo bubbas that they'd waive Marine requirements. Maybe to fill those Marine reserve IP slots, but that'd be it. I know of several ensigns/jgs who transferred after flight school. They didn't have to do OCS, but they did do TBS.
The Marine Corps is so parochial, it doesn't get many who transfer in. To the poster--by the time the Army let you go and the Corps let you in, you'd be way too old to start flight school, unless you somehow quit before getting a service obligation. Then you'd be taking your chances on the Marine side. As Freshy pointed out (there's a phrase I never thought I'd use), there's no guarantee of jets once you're in the Corps, either.
The only way to truly know is to talk with a Marine OSO, though.