Since it's a longshot that anyone here will own any of Bridgeworth's books on collecting Mountain Dew soda pop stuff, I'll reply in general:
A "book value" can be helpful but no more than that. Book value only tells you what one or more of the bottles sold for, once upon a time, in this venue or that. Book values are sometimes inflated -- that is, the author looked for the most expensive example he could find -- because that keeps up the value of his book on values. Circular sort of game.
If you want the bottle for your collection, only you can decide what it's worth to you, $3 or $30 or $300 or $3000.
If you want the bottle to resell, be very careful of what you pay for it, of course.
