Hello jogi,
early Alembics had just one truss rod, later on 2 rods became the standard, I think sometime in the mid to late seventies, but I couldn't tell you exactly when; I am sure Mica can tell you, or one of our afcionados ( and there's quite a few) of Alembics early basses.
However , to find out if you have the real McCoy there or not, find the serial number and post it here on the site for Mica to look up; she'll be able to tell you if it's the real thing plus all the info on its construction specs.
Good luck
Valentino