Those look like 1W low precision (5%?) metal film to me. At least is how they sell them to me, dark brown, rounded edges, as opposed to carbon composite cylindrical same color, or carbon film same shape light brown.
They should take 1W as long as you don't mind them running really hot and some drifting, lower precision allows more power for the same surface area. I'd use them a lot since is the only metal film resistor to be found in my town and for high gain guitar pedals it does make a hiss difference. Depending where I am I usually choose 0.5W 1%MF as general purpose.
JS