well at least with the Contender... picking another caliber is not a problem... also if you didn't get a good grip fit, there are tons of grip & forend styles out there... I like my wood grips for target shooting, but the finger groove rubber grips always seem to find their way on before hunting season...
the pic of my rear sight on my Contender doesn't show the fiber optics well, so here is a pic of the rear sight style on another gun
this is how it usually looks when heading to the woods...