That's the funkiest low seat I've ever seen. Looks like that's a custom seat that either modified an existing low seat base or built a new low seat base to compensate for the missing plastic tank protector. This is what the stock low-seat installation looks like:

The tank protector clips on to the tank with the clips shown here, which appear to be epoxied to the tank.

So when doing the conversion, I guess the PO chose not to modify the tank with the clips to accommodate the tank protector, probably thinking it would affect resale value to have those clips on there, which I assume aren't necessary for the high-seat model (although I don't really know, never having owned a high-seat). Instead, he had a custom seat built up in the front to cover the front of the tank. Bottom line is that the low seat you have won't fit a stock K75 low-seat installation with the plastic tank protector. So it's probably not going to have much resale value unless the buyer wants to do a similar conversion without adding the tank protector. That's a pretty small target market for the seat....but if you DO find a buyer who wants exactly that (including the red strips...not everybody's bag), he or she will pay for it.
You could also sell the low seat with all the low seat hardware -- that might get you some more prospective buyers. There are lots of height-challenged riders out there for whom the low K75 is the perfect match.
You could then take the Gunfighter base and have a seat custom made for you, giving you also the choice of color. I personally am not a big fan of the brown - prefer black leather.
Or you could sell the Gunfighter, keep the low seat and take it to a custom bike seat pro and ask how much lift you can get with gel packs and padding while creating a seat molded to you body type. That seems worth exploring -- saves going through all the hassle of making the low-high conversion and allows you to sell the Gunfighter as is.
I'll post a pic later of my custom low seat -- which is finally busting seams after 12 years.
Anyway -- hope this helps -- Van