An old thread, but I have some insight on it.
I have 2 A1000's. One has a C= logo, one has a Checkmark. Talking to a few ex-C= guys, this is how the production went most likely:
Initial run of 100 machines or so had the boingball logo. Then, Commodore found out that the Boingball was un-trademark-able. (it's an international aeronautics symbol) so they went to the ever to the C= logo for the next few hundred units. However, the Las Gato's guys didn't like the change-a-roo, so they produced replacement patches with the boingball. Then, the familiar Checkmark came into use.
