how can i find out the model or the brand name of my boat?

the boat is fiber glass it is 3.66 meteres long and it is 1.5 meters wide at the forward controls and narrows down to 1,2 meters at the back by looking at it i would gust pre 70’s to very early eighties it is in vwery good nick can see it has had some work done to it but nothing major forward steering and controls also it has a speaker in the middle of the dash approxmaitly 10-12-cm in diameter in the middle of the front dash that stands out weather this is for fm-am radio or cb radio i have no idea all gauges and others have been removed any ideas

look on the back of the boat where the serial number,s are,,if you find these sometimes it will have the make of it,,if not take these number,s and run them through at your local dmv,,and see if it was ever registered,,maybe it was,,and if so they will have the make,,other-wise look on the boat for any kind of name like on the glove box lid,,or anything that has a name,,maker,s always,s leave there mark somewhere on it,,any name you find will probably be the make,,if you find this you can run it on the net here a,d it may bring up a manufacturer that used to build it,,i wish you well with this,,i had to do the same thing once,,but i finally found out,,hope you do to.