Have a 2015 FLHTK with a custom engraved gas tank cover. I want to swap it with a 2021 FLHTK gas tank cover. Does anyone know if they are interchangeable? How about the Derby covers? 2015 is a 103. 2021 is a Milwaukee 8 114. Are they the same size? Before you ask why don't you just measure them, my son has my 2015 in another city and I just bought a 2021. I was gonna go over and swap parts if they fit. If not, I'll get new ones engraved.

 

The derby cover won't fit unless your 2015 is a low or has the narrow primary like on the lows. By gas tank cover, are you asking about the fuel cap door? If that's what you mean, that should fit from the 2015 to the 2021.