Thank you for your input, after posting I did find a MSH1FBA04 instead of 05.
According to this document:
http://archivos.diagramas.mx/otros/R...0fy%20back.doc
both flybacks seem to have the exact same pinout and looking at the photo it looks exactly the same externally, what I don't know though is why two flackbacks that look the same have two different models.