"Swappable" Nut

[Calvin Marks]

A colleague of mine recently got a new nut made for his instrument to accommodate plain gut strings for period music. He has one instrument and needs to have different gauged nut-slots for when he uses plain gut and steel, so he has several "nuts" for different settings. He informed me that his "nuts" are never glued down to the scroll, and that the strings just hold the nut in place. Is this a common practice performed by respected luthiers and players alike?

Cheers