This is the Duroboat Factory.
You do have what looks like a solid boat there. It is probably nudging in to collector category. Not a big money thing but desirable as many older aluminum boats of all brands are now becoming part of boating lore. Your boat will function better than most with big water capability not typically found in light aluminum boats of that era. The no rivet no weld design gives you obvious structural advantages but there are many subtle derivative advantages in your boat that will show up in performance but also make it an easy and worthwhile restoration.
I have gone through your pictures.
Are you sure you have an 87? You have a boat that I would guess has a 1983 or 1984 serial number. last two digits of your HIN will tell you the year.
83 was Duroboats first year in Seattle. Your boat is I think exactly the design that came form Australia in 83.
You have the least sophisticated of transom supports that have evolved over the years. I thought your transom supports had been replaced by a heavy casting before 87. If I wanted to bullet proof your boat I would change it. If I wanted to preserve originality i would keep it but understand its pros and cons. My recomendation keep it unless they are damaged and i will tell you how to care for it so it is never an issue. It looks like this boat was used hard and has managed so far so you should be fine.
Your boat was built before the proliferation of 4 strokes so if you want to go with a heavy motor you will need to pay attention to a few things.
If you want to call the factory to discuss your restoration please do. We love to see the boats live on. Duroboats have not changed much over the years but there are some specific improvements that have been made that are not in your boat. Small improvements over time were all to mitigate different forms of abuse or respond to market issues. Your boat was darn close to perfect when built. if I tell you what you need to know to restore and then operate the boat properly your boat will perform every bit as well as a current boat. I will be able to walk you through every element of your boat so you can identify things to look for, potentially fix and then monitor over its life.
Your boat does not have floors. I don't know if it had them originally I might consider adding them. If you want to stay totally original don't put floors in but they do make life better so if you want function over purity floors are nice.
Once you have a plan for your boat you need to think trailers. You have the old knife blade style keel. It needs to be off that keel roller. Your trailer as it is will not be suitable for a restored boat particulary if you are going to use a 4 stroke or do serious trailering. You can maybe salvage it but a nice galavanized trailer, with bigger wheels, modern hubs and LED lights would be more worthy of your boat. The bad things that happen to aluminum boats often can be traced back to bad trailers or poor trailering practices.
ONE BIG CAUTION Your seats are installed with blind no access frasteners. If you decide to remove them for any reason be very careful. Use pentrating oil to loosen them. If you meet resistence from frozen nuts on the inside they could break and you will spin the screws and have a difficult situation. We now make those fasteners expoed to make Duroboats easier to work on.
There are over 400 pictures of Duroboats at our website. The FAQs may help you. You will see boats just like yours all over the world.
sorry this got so long but I am excited to see the boat get continued life and we want to help where we can.
Have fun. call if you want the advice. When you are done we can get you published on the Duroboat website and facebook pages.