Brownells has the metal Mossberg safety
for $15.00, well worth the price.
Currently own a 20" 9 shot 590 with all the goodies on it for the impending zombie invasion, and a well-worn 500 with a 28" bbl.
Currently looking at gunshows for a used 18 1/2" bbl, or I'll just go to Cabelas and plop down $75 for a new one eventually.