Moderator, SkyTeam and Germany
Join Date: Sep 2001
Location: FRA/STR/NUE
Programs: BA, LH, KL, EY, IHG, Marriott, Hyatt, Hilton, Radisson, H Rewards
Posts: 5,965
I don't know about the FD PIN when checking in online, sorry.
There is no way to check your details other than the KL website if you booked directly with them. If you booked via a travel agent, chances are good that he used one of the big booking engines which all offer tools like checkmytrip (mytripandmore, virtuallythere).
KLM's own system is an isolated application sadly.