Found an old Helios which as far as I know hasn't been used in 40 years. I want to try it out but found 2 small black specks on the inside. Looking through the lens it looks very clear. I think it is dust but I'm new to this so am not sure if it may be fungus. Lens surfaces front and back are smooth and clean. Everything operates smoothly as well so it may be a decent lens. Should I try to open up the lens to clean it? Don't have the adapter yet so I'm trying to figure out if this will be worthwhile.