Sorry for being late - I'm kinda busy these days.
I've got to admit that I've never seen this model before.
My Vantage acoustics have 6 digit numbers stamped on the bracing glued to the backside of the guitar. Both VW models I'm owning start with 80 and according to the existing catalogs I'm pretty sure this means 1980.
But the oval soundhole is a typical element of the Vantage VA series, and These models were introduced not before 1982 (AFAIK).
The "Avenger" Trademark popped up in 1982 too.
Style and Position of the volume knob is matching the 1982 VA series too.
In 1982 VANTAGE mixed headstock shapes as you can see on the X-series bass guitars of the 1982 Born to rock catalog, but my 1982 Vantage acoustic guitar catalog doesn't show a single model with "Avenger" headstock...
In summary: I've got no clue!
Interesting guitar anyhow!
J.