Yes- If oil leak there you'd expect a valve cover gasket leak above or toward the front of the bike. Take a paper towel and follow the gasket line and see if anything shows. If not, check to make sure the oil filter doesn't have a very slow leak- I guess it's possible in the wind that it would find a way up and over onto the header. I'd also look under the front fender, in case you rolled over something sticky and that explains it appearing more than once as it works its way off in the wind.