Re: Capacity Plates
"Many" boats have some sort of serial #, and that's how they originally got registered. I had a 1939 Wagemaker years ago and it had a #, and my current 1952 Lyman has a number.
Nevertheless, some boats did not have a number, hense they were registered with ****. The uniform registration number policy started some time in the seventies, but I don't know exactly when. Look it up!
The plate you showed had a SN. Your boat should be registered with that #. Since it isn't, it is quite probable that your plate was transferred from another boat. Maybe the boat was stolen at one time. I googled your model number and Larson models from that time period and they don't compute.
Maybe you should let sleeping dogs lie.