There was one going the day before for �62 ($110) so the box and manual is now worth as much as the pedal.
I haven't noticed the light yellow knobs before. Mine was produced 3 months after the one in the auction and has white knobs. The manual in the first picture looks white so I don't think it's the lighting in the photo.
We have seen before that on collectible pedals the box and manual can be worth quite a lot. But doubling the price...
I thought about the lightning too, but the pic seems ok.
Perhaps Boss ran out of knobs, or got a shipment where the colouring was a little different. But decided to use the knobs in production anyways...?
It does not seem like a result from aging either. I dont remember the exact date on my PN-2, but I remember that it is from the first year of production, and if the colour is a result from aging, mine would most likely have turned light yellow too.
After a second look, I believe those yellow knobs do look a little different, and have a little rounder tip it seems compared to the standard white ones...
So perhaps the previous owner got bored some night and started experimenting with some knobs, and forgot to switch back...