I was under the impression the fender was different on the RK for fillers to fit?

 

We're talking about older Road Glides....... before they started putting the fillers on them....... or Road Glide Ultras.

But they might fit RKs

 

I just pulled one of my old Part Catalogs out for the filler used on '98-'08.
The reason for the "No Fit" on Road Glides is because of the Antenna hole.
The Filler Strip does not have the hole for the Antenna to come through.
But none will not fit with the Detachable Tour Pak Kit.
Price listed as $89.95.

Part numbers are as follows:
Black Solid Filler Strip 45899-98
Chrome Solid Strip 45898-98
Black Slotted Strip 45897-98
Chrome Slotted Strip 45896-98