I'd look at Google Images, and try to find one that looks like yours. Many times you can then click on a box that takes it to a thread that will have more information about the imaged boat. One thing to keep in mind from what I've gathered, if you find a similar boat in terms to Length & Beam, in the Specifications even if it is not your exact model, the safety in terms of maximum HP outboard and total weight including passengers and equipment will probably apply.
Did a quick search, for Sears Gamefisher and found some similar:
https://www.google.com/search?q=aluminum+boat+gallery&biw=1014&bih=637&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwjSpNiUma7LAhXD2T4KHX1uDQEQsAQIGw#tbm=isch&tbs=rimg%3ACYBQFtAFL_1bTIjgySvpyYjhU9mEtW9fqp4sw7xRGy8i7Y7PQIM8FlKCY5m0VzmnK6nkA7KVmxEYrGIWj5s9Vft0okyoSCTJK-nJiOFT2EerqqYR4JLQRKhIJYS1b1-qnizAR6uqphHgktBEqEgnvFEbLyLtjsxH9_1kBfh7wqKyoSCdAgzwWUoJjmEekcAgP7UcgmKhIJbRXOacrqeQARqqfwmOUGZk8qEgnspWbERisYhRGPWzE-PFKYcyoSCaPmz1V-3SiTEc1Z5tLfbvqC&q=sears%20gamefisher%20aluminum%20boat&imgrc=WRQWQ_4Fzl9-DM%3A
https://boats.smartcarguide.com/listing/49451088/
Happy Hunting...