thinking of buying a 70 mach 1 need help

Hi everyone for a long time i wanted a 70 mach1 and finally saved for it i found one in mint with 4 speed and in a dark green with all the bells. it had a full restoration the zin shows it to be a H code the seller said it has a M code 4 bl in it is that something i should be concerded with for resale down the road. I like the car and plain to keep it for some time but i can't loose a lot of money, since there are a lot out there should i just keep looking. Any help would be GREAT