That scan site is a god send, I use it all the time to check my PCBs so who ever did that page thank you.
I seen Xian Xis stuff, but I like to make my own..something about doing something your self makes it better. I haven't touched that metal slug label yet, but I've never seen a cart without the serials (other than jap carts now). Be nice if it was real though then all my slugs would have legit labels.
I never noticed some of the Japanese carts didn't have them tho you made me go look. Lol
I didn't know about the metal sticker things either so thank you for that bit of info!