I can tell you that removal of the alternator will result in oil getting on the exterior surfaces in that general area. It may not be a leak if the PO had the alternator out......did you try cleaning it off real well and then see if it leaks more?
I cleaned it and then let it idle for 5 min. and that is when I took the picture.
I went ahead and removed the alternator to find the o-ring was damaged and whomever was "in there" applied a lot of sealant in an attempt to avoid putting on a new o-ring

Why they wouldn't put on a $5 o-ring is just laziness. I will go get one and solve this little problem.
BTW the Valk has 30K miles.
Mike