I just sold my 2011 voilé mojo RX for EUR 400.00 in Europe, skins & voilé kit included (but no sliders plates) - the condition was like new, used only twice... Some people sell brand new boards for EUR 450 around here, voilé kit included (which would be the equivalent of $450 when you deduct the taxes)
While the older split decision boards are of a better quality (I mean, much more durable than the new ones), they're also heavier and usually stiffer (which is a great quality for me - but might not be for others...).
I think $300 is ok if it's in great condition, the skins are not crap and they still stick well.
If it needs repair / if you need to glue the skins, I think $300 is a bit much, try to get them around $220-250
And don't forget, the split market just blew up... many manufacters now sell splits - you can have brand new ones (last year model) for up to 1/2 the price - many sellers still don't acknowledge that fact...