https://thegreatmodel8.net/

I never really paid much attention to the underside of 8 forends but they can sure be different from one to another. The FE on the left has a raised wood bridge. The right has a stamp of the letter ' N '. I looked at another 8 yesterday that had 3 numbers stamped on underside of FE that did match the rifles serial # ... I guess the FE'S could have been swapped ..... your thoughts ???? on these variations and are there more to watch for.

My understanding is the answer is yes. (I know the folks here hate that answer too.)

Yes, as you know, of course they could have been swapped but ...
I have noted on mine, as have others on theirs, that Remington was not too concerned regarding the furniture on "A" / standard grade rifles as oppose to the higher grades. Some standard furniture has serial numbers; others don't but still appear to be original to the gun. As to the "N" - don't know? I also believe there is a bit of a size difference and slight changes on the M8 forends over the years. (There certainly is on the M81.)