How do we handle parts which exist in several different versions?
If the parts have different numbers, just use the different Lego numbers. More commonly, the different variations have the same number. This is managed by adding a single alpha character to the end of the base part number (e.g. 3626A.DAT and 3626B.DAT, the solid stud and hollow stud versions of the minifig head). If, prior to the second vesion being authored, one version of the part was released using just the official part number (no alpha-character suffix), it should be renumbered/moved to use an alpha-suffix.
