Considering that many folks here hve done complete rotisserie body-off restos here and on other sites, it seems funny that no one would have found this magical secret location.
I mean, some folks here have been over every inch and then some of their cars.....
Chop shops would be more likely to find this "secret spot" than an average owner....after all, the yare chopping and trying to sell the parts.....dontcha think they would be looking extra close for stuff like this?
Plus, if this number were on any part other than the frame or body, who is to say that it would still be "accurate" unless its a 100% original car? And even then..who knows....