Well, I'm 100% sure that you're 100% wrong. I own 6 of the original W6 subs and they look nothing like that.
The only JL subs that did not have a pole vent (like the sub in the pic) were the W3 and the W0. The way to tell the difference between the two is the number of voicecoils. The W0 only came in single coil and the W3 only came in dual. Looking at the pic it is a single coil and thus a W0. I wouldn't pay $50 for it but I never really liked the W0s.
There is an outside chance that the small spec in the center of the motor is the iny pole vent that the W1 series had and that this is a 15W1 but I don't remember the 15W1 having a magnet that big. Better pics would help a lot.