I am doubtful about that MIC. The HIN you list is missing a character. There should be 12 alphanumeric characters.
Secondly, it looks like there is a gap on that HIN plate at the beginning that is the size a missing character would occupy. If that is so, the manufacturer’s identification code is actually “xMA” not “MAO”. If you put any letter of the alphabet from A to Z in front of “MA” you will get a valid MIC.
Lastly, the last four characters of that HIN are appropriate for the “straight year format” that was in use in 1976. The month and year of certification are denoted by the last four characters of the HIN. The characters “0676” would therefore indicate a hull built and certified with the US Coast Guard on the sixth month (June) of 1976. There do not appear to be any characters missing from the end of that HIN so one must be missing from the beginning.
The five characters between the MIC and the last four denoting month and year of certification could be letters, numbers, or a combination of both at the manufacturer’s discretion so long as each five character code was unique to a specific hull.
So you have 26 possibilities for the maker of that canoe but Massimo Marine is not one of them.