The picture shows my friend's collection of Philips PL-C 2P, made in Holland. But one dealer believes it is fake. May I ask everyone to see if it is real or fake?

I'd say this is original. Capacitor used here looks European style, also using well-controlled welding says for high-tech manufacturing.

IMHO.

I'd say genuine Philips, not fake.

I agree it looks genuine.  One fairly sure way to confirm would be to break open the discharge tube and look at the colour of the metal wires in the stem seals.  Around the time this should have been made, Philips switched away from the usual dumet wire (red colour in the glass) to Vacovit 485 alloy, which has a kind of greyish-green colour and originally introduced by Osram for its Dulux lamps.  Since it was more expensive very few other manufacturers copied that material.