That looks just like my old one, from which I derive my handle. The N for natural was always hand-written in a grease pencil type of thing, so the regular EB2 stamp would have the "N" after it. It is very probable that they did not bother trying to reach in and do it if they forgot to before they stuck it inside. There is nothing about that one that leads me to suggest it is refinned or stripped. In fact, just the opposite - if it had been a burst it would not look that clear at all. Mine had not a speck of checking at all. I even bought it on a chilly day too, for all of $150, so if I couldn't craze the finish nothing seems out of sorts there. It gives me passion to gaze upon it. And its original case, all pink inside. Well, enough of that.
$20g's is freaking bathouse for a bass that has such limited demand though. No Gibson fan would want one (of 6 made that year, if I am not mistaken) to the extent that they would spend a dollar figure comparable to a vintage custom colored Jazz or P, which will always have stronger resale. Penny wise, Euro foolish. But what would be resonable? A couple of years ago I would have thought $3k. Now, I am not sure. I would imagine less than $10k. These things do well until they cross over the line of making someone ask "How much reverse or non reverse Tbird can I buy for that much?", or "How many Jack Bruce type EB3s can I buy?" In each case you would have an answer that would make more $ sense than that. Unless you really love the Flamingos bass player.