That looks legit. Most of those older US labels don't have serial numbers on them anyways. The serial number is on the silver "warranty void if removed" sticker that is stuck on the side of the cart instead.
Also, those old style labels are horrid quality anyways, they just kind of feel like paper, and immediately look awful the moment they get creased from opening the cartridge, get any moisture on them, collect dirt and stairs, rip and tear easily and you can't clean them without making them just look even worse, and they just feel like paper, or at most, magazine print quality crap.
I do, on the other hand, love the holographic labels put on later carts. You can wipe them off to clean them, they last much longer, look better, feel better and actually do lend some authenticity to the cartridge and as far as I know, nobody reproduces them accurately enough to fool anyone.
A simply laser printer with sticker paper can produce a pretty nice basic label, although I prefer to print my repro labels on this frosted transparent sticker material, then stick that on plain white sticker paper, then apply that to the cart. It makes a label that looks like the original label, but feels better and holds up to cleaning and stuff. Also, I think it's just nicer than the original (while still looking identical) but also not trying to fool anyone.