Certainly makes one wonder how the right case and cam chest could possibly be modified to go from the unusual geometry of the K Model valve train and tappet blocks, that mount with 2 fasteners each, to the XL tappet blocks that are totally different geometry and mount with a single fastener? Is the right case XL and the left case K Model? Matching XL belly numbers say no.
Also not clear how you use K cases and go from the 2.75" K Model bore to the 3.0" XL bore, which requires shifting the crankshaft to the left, which in turn necessitates shifting the primary drive left. God only knows what's in those cases, and even he might not know. Lot more questions here than answers. If it looks like a Sportster and smells like a Sportster it likely is a Sportster. Would love to see an image of that left case primary drive with no trapdoor in it.