Your call, but its 100% not a 500 one, you can even see where the v has been cut out through the double sided tape in one of the photos, the 500 ones also have a mould line through the cut out area.

I have a brand new one of the type you have, still in its box up in the attic and I paid £250 for it so I am not saying yours is not valauble, but 500 owners know there stuff and you may get hassle after the auction closes if you list it as a genuine 500 item

edit - just seen the pics above of a genuine one, compare yours to these if you need confirmation