The key thing for this gun will be the quality of the barrels. If they are heavily pitted (often the case in wildfowling guns), and < 50 thou in thickness, then using this gun with the loads originally intended could be risky. Many 8 gauges also have ring bulges on their barrels which can be seen with care, but without awareness, are an issue waiting to happen. If you can get a good quality micrometer to measure thickness, this will help as it will show depth and whether the barrels have been lapped out in the past - another issue not immediately visible to the naked eye.
I am struggling to see the inherent quality of the gun in the pics so far, so if there are better and clearer views of the action, the level of corrosion on the barrels, and the condition of the stock, especially around the action and grip, it would help to form a view. Quality is everything - a poor quality model here in the UK can be 1-1.5k as it needs plenty of work/may not be shootable. A good/very good quality gun is generally 6-10k, with a small number north of this.
Craig.