Some pocket doors do have an adjustmen at the top. Usually it is simply adjusted by loosening two screws on each hanger and lowering the door. You have to realign the closing edge against the door jamb as part of the adjustment.

Were the doors ("Converging Door Kit" according to Johnson) installed after the floor was in? Then the header should have been lowered 3/4" per instructions. Don't think you're going to make that up by adjusting the hangers. You can try - might have to remove some trim on the clip side to be able to access it. Just turn the bolt on each hanger until the door is the height you want and hangs level. Might be a little trickier with converging doors.

Most likely you'll run into the problem we had where the bolts are too short to adjust that much (out builder put frame 1" off subfloor since they were "cut for carpet" and we have tile, he didn't listen when I told him the finished flooring would be 1" thick). They kept falling out of the rollers since we only had a few threads screwed in. Jhonson doesn't sell long bolts and the heads are special. Brickeye suggested getting threaded coupler and having threaded rod cut to extend the existing bolts. The size is 1/4-20, I had Ace cut 1" long extensions and round off the burrs for me. You'll probably have to add trim to hide the hardware and new gap at the top of the door, just as you would to hide the track on a bifold door.

If the doors are painted it might be easier to add a filler piece of 1x material on the bottoms, sand flush to the faces, and repaint the doors. My doors are stain grade. HTH