Did you find a parts manual? I have one if you need it. It covers the KY (Spec A-P) and KYD (Spec A-C)
Looks like a big job to replace that crankcase gasket (101-0788) .
I tend to agree, these gaskets don't go bad. A couple other suggestions:
You might attempt to re-torque the cover bolts, take note if any were loose.
If you can pinpoint the location of the leak, you could try mixing some JB weld and use a cotton swab and run a small bead along the seam to see if that will plug the leak.