chaadster, the bike was new at the time I converted to a drop bar ATB. Yes, they are common now, but in 95 not so. Used a set of long reach side pull brakes. I don't remember exactly the brand or model of the brakes, and they may have been BMX side pulls. To change back to ATB the wheels had to be changed and the handlebar plus controls. It was about a 40 minute process.
My vision is a mountain bike can do anything you want it to do, whereas a gravel bike is limited due to tire size. As the tires grow wider, so must the frame, hence they become ATB. Oh, one more thing. Head angle will go from 72 to 71 + 45 rake as they should have been all along. I hear complaints from gravel bike buyers that they want more stability on gravel. The way to get it is wider tires and more trail. Just like a mountain bike.