It looks like it is not off that much. You should carefully measure the rehaut opening or even make a round template (plastic, cardboard, etc) that fits perfectly in the opening. Then place the template on the dial and see if there is room to shave the dial without eating into the minute tics. Also with the template in the case and the crystal off you can scribe an arc with a very fine tip marker that denotes the rehaut opening. Once you know that measurement you can assess whether or not the minute tics would be truncated, i.e., obscured by the rehaut.
If all that looks good, it's time to shave. You can DIY it without a lathe by using a dremel.
DIY Dial Shaving
If there is only a little bit to take off you can do it by hand, the same way an insert outer diameter is shaved. Tape a piece of 400 grit sandpaper flat on a bench. Wear a latex glove, hold the dial on an angle so as to contact the backside first. Hold the dial by its edge near some markers so if your finger contacts the face it will touch a marker and not the dial. Swipe roll the dial toward you on the sandpaper, 3 - 4 swipes, then regrip and do the next overlapping arc. Use a dust blower frequently to keep sanded particles off the dial face. Measure often. Keep it even all the way around. Finish with a higher grit 800 or 1000 if desired.