SASDesertRat,
If it were REALLY NIB it would have both magazines. That can be a bargaining chip if you want, because if they are asking $500 because they think it's a collectible it is MISSING a magazine and they have changed magazines plenty over the years so even if a new one fits it likely won't be exactly the same.
If that's what you want then a pre-B will be worth more than a B model, but not much.