One of my early guitars was a Stella 12 string bought for £25 (new)in1963 in Frank Hessy's shop in Liverpool. It was plywood and the neck was a thick log without a truss rod. It played well but needed fingers like Mole Grip Wrenches to play beyond the third fret.
Sadly it was lost when I loaned it to a travelling person whose Bender was set on fire by louts.
Fond memories but it led me on to far better instruments and even to make my own banjos & guitars which all have necks which are truss rodded & playable