It looks a lot like my PSW650 as well. My sub was finished in gloss black on the front, top and back. The sides were satin black.
If you are having problems with the sub, you are out of luck. The PSW650 is over 13 years old. The amps on the Polks tend to fail after several years (sub amps all seem to die prematurely, probably because of the vibration from the drivers). One of mine (I had three of them) failed last year and Polk could not supply a replacement amp nor could they repair it.
I ended up selling the other two a few months ago even though they were still working... I ended up with a DefTech SuperCube 6000 (that was a waste of money) and building two subs from scratch.
I will be rebuilding the sub in a new cabinet from scratch in the near future with a Dayton Audio 250-watt amp.
If you are interested in rebuilding, look at an 18" cube with the Parts Express DA 250-watt amp. You can either keep the original ports (which have to be relocated, face down to accomadate the new amp) or design a rear facing rectangular vent 15"W x 2" H and 15" deep in its place.
If it's not a BIG screen, it's not a theater...