If you don’t find a hipo part, a normal C4 body can be used with minimal changes. There is an old thread on this site from 2009 and this s-techent site has some info.
Given that automatic hipo's are not everyone's cup of tea on this site, those who DO have an automatic hipo have a vested interest in KNOWING that the internals are the real deal..I have such an animal and am now actively trying to compile a list of those who have one too. Bob Mannnel and I have spent some time, energy and money getting info accumulated to address C-4 questions and challenges, and a sub-circle of friends here who have the same transmissions would be a network worth putting…