My L-Bow V is now, since this morning, with Heiko for a complete check-up, some repairs as there have been some modifications made over the years, and the fitting of the new preamp version.
According to him it's one of the very first ever made from 1998 or 99, he's checking his database to find it, but needs to find out some other clues than the obvious lack of truss rod; the fact that the paint is not original is not helping, but I'm confident.