Sorry, modbend, that's just not accurate. Reference images of IN-50 on HM site.
As far as I know, prior to sometime in the 1990's, authorized versions were not marked in any way and some knockoffs were so close to authentic as to be virtually indistinguishable. If dimensions, glass thickness and edge detail, wood species, and finish all seem correct, it could be authentic. One detail to check would be the connecting pin. It should be solid with solid alignment lugs (which appear to be a tad short on yours?).
https://www.designaddict.com/forum/General-discussion/Authentic-Noguchi-t...
the glass thickness is also distinguishable (if original to the base), older herman miller catalogs or reprints list them as 7/8" thick & later & current versions 3/4" thick (most replicas are 5/8" or 1/2"). the very early glass (again if original to the base) also has a light green edge, later dark bluish green & currently almost charcoal grey/dark. the pin & the base looks original or close to looking at the images you provided.
modernica in los angels made exact replicas of these table in the early 1990 before herman miller reissued them again as part of the herman miller for the home in 1994.
If you need any help, please contact us at – info@designaddict.com