I read that National Cue Co was only in Chicago for one year in 1968, then moved to Georgia. Huebler, Meucci, Helmstetter, worked with National but of the first cues Paul Huebler built, I have not seen that quality of craftsmanship. I have a few early examples. The design screams Huebler, but not 1968, unless Paul stayed behind and built it much later in Chicago.
If I were to guess as to the timeframe, I put this cue at no earlier than 1975-76 prototype or early custom. On the other hand I have not seen any of his with brass insert that late. This also may have been a Meucci/Huebler collaboration just prior to parting ways.
If the cue is for sale I may be interested.