My recollection, and it is a bit cloudy, is that the 250/370 RM A were out before the 125A. I had a paper run that took in the local suzuki shop at Padstow and was a regular gawker at Hazelton's in Sydney and can remember both the RM and RH- although I didn't realise what was involved , I do remember a price difference.
Taking a punt, I reckon the RM125M would have been out before the RH250M.
Suzuki were very keen to show their strength in the 125's.