Texman ... They must all be poring over their Master Parts Catalogs to see if the parts numbers match...
Is it safe to assume that you need a running board for a '40 and you've found one from a '42? Any chance the seller will let you fit check, or is it an item that needs to be shipped to you?
Hopefully someone will be along who can answer this for you.
If not, give he guys at Jim Carter's a call (see our Links Page) -- somebody there might know.
Regards,
John