I think this is an assembly line manufacturing issue.
This is a cropped picture of the Blitz oil pan, a modified OEM pan w/ the turbo oil drain tube.
There are no issues with paint on the bolt and washer... my original bolt however, did not look the same when I took it off my car:
http://www.ft86club.com/forums/showthread.php?t=54142
The Blitz oil pan was purchased as an individual unit originally from Toyota/Subaru, and the paint is much cleaner around the bolt.
-alex