Would looking at my parents/grand parents/uncles from both sides of the family provide an accurate image about copd predisposition and smoking effects?

Not necessarily: Genetic predisposition to developing COPD is not straightforward, and there are very few people who are heavy smokers who do not sustain SOME damage to their respiratory tract. I would also point out that smoking can cause more severe acne and make it harder to treat as well. Why play Russian Roulette with your life and your health? If you don't smoke, don't start. If you do, get help quitting.