Not a problem. The factory fill is very good oil. If you don't believe me, look through all the used oil analysis that people posted here:
http://www.ft86club.com/forums/showthread.php?t=13286
This is my report with a 4.2k mile test (factory fill) and 5.7k mile test (first free oil change at dealership), you can see that Blackstone has no problem with the results, and even recommends running more miles because the TBN shows plenty of active additives left.
http://www.ft86club.com/forums/showp...&postcount=308