steve650cc

Help needed please, I have just bought a Montesa with a 1970 Cota 247 engine, but I have been unable to identify the frame. I thought it was a bmv motoWhitlock frame but Mark Kemp from bmv moto who has been helpfull says it isnt -so any ideas please, the only markings on the frame are on the front of the headstock -MOT2. Thankyou to the people that have replied up to now - and yes I do think it is almost a replica of a standard frame but with what appears to be bronze welding and strengthening, so I wonderded if it was indeed a Montesa frame ? maybee specially prepared for a specific rider? Any more ideas welcome.