George Nelson Floor Lamp Quandry  

I was given this lamp by someone who has since passed away.
He worked at the Herman Miller factory for many, many years.
The shade is a little taller than the standard bubble cigar floor lamp but more importantly is the base. On the bottom of the stand there is stamped F-154.
I have asked Herman Miller and after consulting their records I am told the F-154 is not their nomenclature.
My friend worked for the company for years and I know he not have bought this lamp elsewhere BUT he might have gotten one offs from the production line.
My question is, does anyone recognize the base of this lamp as something other than George Nelson/Herman Miller?
Thanks in advance!