You would think that their value would start to climb back up by now with collectors, with the low production numbers, and rarity of these magnificent machines.
Marty
From our mouths to God's ears Marty! If only that were so...

Unfortunately and no matter how much we like them they are still little known outside our own community. Their small numbers originally combined with years of attrition and things like Marelli and other parts going obsolete mean they'll also get more difficult to maintain; which means even those optimistically familiar will have less interest. Screw all that. We love 'em. That's good enough.
Of course my bike isn't
completely stock. Have done a few things to offer concession to modernity and make service more feasible if I ever crap out away from home. The old swingarm is gone, Marelli has been swapped for the uber common mid 2000s Delphi and a few other things to make it just a good easily maintained old bike. Hell, if I ever get around to installing it there's even parts here for a cool engine upgrade as well. Even that is done with reliability in mind as much as performance. Though the power coated and diamond cut heads and jugs will certainly look cool. As well as it handles the duty now it really will be a trailer pulling machine when I get a chance to get the work done.
There will be one downside to getting that engine work done though. Even though it's mass is greater and it's drag coefficient is like a big person's butt compared to the Road King the SERG will be both quicker and faster than the SERK when the Road Glides gets it bits. So the Road King will whine; and that will cost me more money (probably) next winter. Oh well.....