3 x spark plugs

[M.W.Miller]

Hello, I purchased some boxes of model A parts, And included were four 3 x champion spark plugs still in the boxes and rapped in the wax type paper. They look like Nos. I know that these are now being reproduced and are very authentic to the originals. Just wanting to know if there is a way to tell originals from the after markets. Thank you. ..Mike