I can see how you would think that, but I've seen wide variations in the length and shape of the tab piece on the sides of the bag. I own a basic bag with a glued-in serial number that has an elongated tab, similar to your newer bag. The hardware is slightly thinner, like your older bag. This would make sense because the older bags were more likely to be solid brass and since that hardware was heavier (and probably more expensive to produce), most hardware on older bags is thinner. I used to have another basic bag also with a glued in serial number that had a short tab on the side like your pre-serial number bag. It also had thinner hardware. I don't remember ever seeing a zipper quite like that one. I believe both bags are authentic.
ETA: I didn't think I had ever seen that anchor symbol on the strap's dogleash clip, but in examining my NYC basic bag, it has the same symbol, but at the base of the clip near the swivel. How exciting to find something new I didn't realize was there! I've got to be more observant!