Polerouter question -- 20217?

I bid and won the below, but I have some worries about whether this is a legit Polerouter given the inconsistency in serial number - dial etc.

Description reads:

• Reference: S20217-3
• Movement: Automatic, calibre 138SS, signed and in excellent working condition
• Case material: Stainless steel
• Diameter: approx. 35 mm (without crown)
• Dial: Original black dial with silver inner ring, in beautifully preserved condition
• Crystal: Plexiglass
• Crown: Signed

What do people think this is?

Unfortunately, as you first guessed, the reference suggests this watch should feature a white, non-lume dial. Moreover, the black dial currently mounted is a poor-quality reprint. Most probably, they reprinted the original white dial in black to make the watch look more appealing. The crown, while stylistically correct, does not appear to be signed and so not original. If you have the chance, I will do everything possible to return the watch whatever amount you paid.