MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
You are right, the 2 front guide wheels have 4 bearings each, so this makes 12 x 623 ZZ bearings.
I have bought more than needed, and it was the only picture (https://www.youtube.com/watch?v=LmtvaULC_Ls&feature=youtu.be&t=138) I took with all of them, before starting the assembly. Sorry for misleading...