The one odd thing that I just remembered is that the followers have what looks like Sharpie marker down the top length. But it wipes right off on your finger. I cleaned it off but I have no idea what that was all about.
A S&W sales rep told me something along the lines that after they test fire the pistols at the factory they mark the followers as a safety check to verify the magazines are empty before they pack the pistols for shipping. I know when I was at the factory they ran at least one full magazine through each pistol.