The mileage is not an issue, your issue is that it probably has never been done since 1997. You probably have OEM grease in there form the Mothership. I did them on my '97 WG around 25k miles. both bearings though OK, the grease was like chocolate cake batter. I was glad I went in and cleaned them up and added fresh grease. As stated, no reason to remove the lower bearing, just clean and repack with fresh grease. Good winter job, probably take half a day. Fall away after is crucial, the FSM explains it well Good luck.

 

I'm inclined to suggest checking your steering head bearings at the specified intervals, taking into account Architect's observation above about servicing them within a reasonable time, such as at 25k miles. I actually replaced mine at around 35k miles, as I had a lot of work done to my Glide, including repainting the frame.