I have acquired an old 12 string guitar which looks just like a Harmony Sovereign 6 string I had years ago.

There's no label inside or any other markings, and the headstock has a faint logo shadow remaining - Folk 12.
It has a zero fret and a double saddle. Most of it is original, but the wide tailpiece has been replaced by a narrower one - the marks of the original remain. There is no truss rod.

It looks very similar to one played by Pete Townshend of the Who.

Any ideas on origin, age and maybe current value?