The pink gradient is the main one that springs to mind. It is a different shade between original production runs (hot pink versus standard pink).

The reason is that three different production companies were originally contracted out to do the original playfield runs and all used different colour schemes (Lenc Smith, Sun Processes and TAG)

Some of the playfields are also missing the diamond plate logo.

I guess it will depend on whichever files IPB used from the original production run.