Doesn't that require replacing most or all of the center console?  Moss has a new center console for $299.99, but it's not like the original.
https://mossmiata.com/1990-1997-miata/interior/redesigned-center-console-by-il-motorsport-1
Also, try Redline Auto Parts.  They part out Miatas.  They don't have any '90 glove boxes right now.  They're currently parting out two '94-'97 models, but they expect they'll get earlier models in the future.  Check with them.
https://www.redlineautoparts.com/mazda-miata/1990-2005-na-nb-miata/?sort=newest&page=6