Well, I knew this would happen at some point.
Typically, the rule of thumb has always been:
Licensed NES games are originally sealed if they have the horizontal seam on the back.
A guideline like that makes it easy - no seam, not originally sealed.
WRONG!!
I bought a Namco Pac-Man sealed MINT off of eBay. When I got it - it looked brand new in EVERY way - perfect! However, NO horizontal seam on the back. Also, the shrinkwrap was a little thicker and not malliable like the other sealed games I have. So, I immediately checked another sealed Namco Pac-Man. Sure enough - it had the horizontal seam.
OH SHIT. I've been duped! (or so I thought)
Figuring that it was not originally sealed, I opened it. I was dead wrong. It was as pristine and untouched as the day it left the manufacturing line.
Anyway, the moral here is that the old rule means exactly shit.
Just because it doesn't have the horizontal seam on the back doesn't necessarily mean that it's not factory sealed. I know that's already true for the majority of the unlicensed NES games, but I can definitely say that it can also be true for licensed ones as well.
Just an FYI.
Steve