Small amount of oil at ends of exhaust...?

So the idiot that I got this bike from turns out had no business touching anything with a combustion engine, I just did a oil change since I just got the bike and it turns out he had " topped it off" before I purchased it I'm assuming he checked it while I was cold and had been sitting because it was overfilled by 1qt... Maybe 1.25 qts, I changed the oil and got the level correct I'm at the top end of the dipstick but a hell of a lot closer than the ******* before, I guess my question is would these be from it being overfilled? Or is there cause for concern? I don't see any blue smoke when I start it, and when I had the air plenum and that off I saw no residue... Maybe crank case vent? PCv valve? Any help would be appreciated, another thing I noticed is when I am down shifting and I blip the throttle it will "pop" / "backfire" if you want to call it that it sounds pretty muffled but you can definitely hear it, mainly from the left side exhaust, potential loading up? Or leak on the exhaust?