It's identical to the Epiphone ET series Crestwood of the same period save for the headstock. The specs for the ET should be identical to the specs of yours as they were both made by Matsumoku.
I can't find any documentation on it here, even in the catalogs I've not had a chance to add.
I had two Crestwoods and really liked them. Surprisingly nice guitars given the period.
Several of the Epiphone series of that period had Aria twins.
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Epiphone ET-290
1974-1978
Body:
Maple body
Neck:
Bolt-on Maple neck
Rosewood fingerboard with pearl block inlays
24.75" scale
1.68" nut width
Binding:
3-ply neck and headstock
Electronics:
Two humbuckers
2 Vol. 2 Tone controls
3-way selector switch
Hardware:
Gold hardware
Tune-o-matic bridge with stopbar tailpiece
White pickguard
Stamped tuners
Colors:
Cherry Sunburst
Cherry Red
http://epiphonewiki.com/index.php/ET-Series