It seems unlikely. We know that many collections occurred of words only as the tunes were thought unimportant, and it is entirely possible that accompaniment was similarly marginalised.

We know that some songs are set to the tunes of tunes (Johnny Dhu - Scotland, and one of the name of which I am not certain - maybe "my good days are done" - a Northumbrian tune - to name but two). We know that some songs appear to be in the same mould as fife and drum playing which was used for military song. We know that ecclesiastical music (which plainly powerfully influenced some of the harmony work of the Watersons) had been accompanied since the the end of "pure" plainsong.

Music hall music which by the dates of much collection had already influenced the corpus of traditional song was usually accompanied. Surely the same argument can be made of the Wheatstone accordian and sea-song, can't it (I don't know, I speculate).

I thought that some source singers (and I thought that one was Margaret Barry, didn't she play the banjo?)

The travelling minstrel must surely have influenced the traditions, and many were lutenists were they not?

I cannot at the moment place where the line comes from but "Ye mid burn that old bass-viol, that I set such value by" surely points to the use of the instrument in tradition. Why would the tradition have segregated the instrumentalist from the singer?

It doesn't feel right that what is suggested should be so.