Sorry for the delay in sending out a sincere thank you for the responses. I'm sending the info to my wife's friend so she can pursue further if she wants. Thanks again.
In the 1981 Directory of Contemporary American Musical Instrument Makers Thomas F Johnson is shown as a full time instrument maker since 1967 with one employee. He made guitars and dulcimers. I don't think the North Texas State instructor is the same one.
I believe this is who you are asking about: http://music.unt.edu/faculty-and-staff/thomas-johnson
I would not hesitate to contact him via his email on that website. Good luck.
My wife's friend bought a dulcimer at an estate sale. The label inside says Thomas F Johnson Classical Guitar Construction Rte 5 Sturgeon Bay, Wisconsin Jan 1976. Has anyone heard of this builder or is any one familiar with his dulcimers. The picture I have would seem to indicate the dulcimer is probably walnut and has heart sound holes.