Reporting back.
I planted Clemson spineless seeds. Yesterday I was able to pick enough to have for dinner. Anyway, as you can see, the two bigger ones on the left have the fringe. The four others on the right do not. The two that do were picked from two different plants. I will do further investigation to see if the same plant produces some with fringe and some without.
Edited to add: It's the more mature/bigger pods that have the fringe......