The Indian made copies of the Mk4 Sterling, known as Carbine Machine 9mm 1A, are usually stamped SAF indicating manufacture by Small Arms Factory Kanpur, however here is one stamped OFT indicating manufacture by Ordnance Factory Tiruchirappalli (Trichy).

OFT was established in 1967 to increase production of small arms in India, assisting RFI (Ishapore) and SAF (Kanpur). Online info about OFT products does not mention 1A production, has anyone seen any other OFT marked 1A ?