Knoll label history question  

I was wondering if anyone knows when Knoll ceased using the paper label that reads "H.G. Knoll Products Inc."? I am curious because I picked up an old Saarinen stool and it has that label, but it seems weird to me because Hans Knoll died several years before the Saarinen tulip line went into production, I believe.

Edit: since asking this I have found other Saarinen tulip line pieces with the HG Knoll Products label, so it must have been in use for a bit after Hans Knoll's death.