Thread edited as it was chain lube/oil . Looks like dealer or someone used oil for chain lube which has been thrown up back of engine area, cleaned off and all good
Just had another look and i think its the sprocket oil seal leaking and throwing oil up rather than valve cover
Rear rocker gasket is common on the V4, especially early bikes, no matter the milage. Front countershaft leaks can happen too but i believe not as common as the rocker. To eliminate the countershaft leak or rocker, clean the areas thoroughly including the chain. (Don't lube chain prior to your test ride) You can use a aerosol foot powder spray (yep athlete foot powder) around the area you think it maybe leaking, it will absorb the oil and you should be able to trace it back. My 22 V4 rocker leaked on a very hot Mugello TD and sprayed small amounts of oil over the rear tyre. I had removed the black plastic covers off mine which didn't help with the way the oil was sprayed all over the place. The covers probably would have reduced it.
