Once, a long time ago, I had a toy KLM 747 and I remember very well the registration was PH-BUJ. Since then I have seen more models with the same registration and, if I remember correctly, even a poster of this aircraft (not sure though!). The model I owned was one with a short upper-deck, I'm sure about that. (However toy manifacturers are not well known of their accuracy!)
About the meaning of the word BUJ: As far as I know there is none. So it's no swear or 'dirty' word. However, BUI means 'rainshower' and BUK means 'bend over' so maybe it should have ment anything

.
The first 747 operated by KLM was registered as PH-BUA and named 'Mississippi' and the BUI and BUK are indeed named after aviators, so it would be very strange to put another river (Hudson) in between.
But, it's all speculating, I know! If you really want an answer, why don't you try asking KLM themselves?
Link to their e-mailpage
Good luck!
Rog?!
[ 08 October 2001: Message edited by: Red or green?! ]
[ 08 October 2001: Message edited by: Red or green?! ]