Topic: 65 / 66 FORD hood letters - how to tell NOS vs Repro

[jk66gt350]

Cleaning out my workroom the other day I came across some new, perfect condition chrome letters that I believe are for a 65 or 66 Mustang hood that have been in a cloth bag for about 25 years.  They are loose, not in boxes.  I am trying to determine whether they are NOS or repro.  They have very small numbers on the backside of them that are hard to make out - similar to what are supposedly NOS letters I've seen on ebay.
I was thinking of selling these but do not want to mis-represent them.  Can anyone tell me how to tell for sure whether they are NOS or not?  Thanks, John   

[CharlesTurner]

The originals usually have small numbers like you found.