'Rinty' or 'Rudy'?

I've always thought Rin Tin Tin K9 Cop was re-edited from Katts and Dog for the US, but now I think it's the other way around! After watching several episodes of Katts and Dog (the only versions of the show I can find until an official DVD is released), I'm surprised to see how often "Rudy" is called "Rinty" in those episodes. In some episodes, he's called "Rinty" for the whole episode (see the Katts and Dog version of Hit and Run for example). The opposite never occured in the US version as far as I can recall....