Absolutely - we have a glaring lack of players who can penalties efficiently, and he has plenty left to offer as a third liner.
And to try and nip the following argument in the bud, we do NOT have a glut of third and fourth liners. There are quite a few guys who may be penclied in for those roles, but that in no way means they cannot be improved upon.
McEachern - Pirnes - Brown is a pretty solid 2-way third line.
Just because you have players who are destined to never rise above 3rd line status doesn't mean you have to settle.
Belanger could easily be let go and Armstrong must play with offensive minded players in order to have any impact what so ever, so he won't be on the 3rd line. It might be bush-league to not offer Kostopolous a contract, but that doesn't mean you have to.
McCarty would be a fine pick-up, and I'd support this line-up:
Frolov - UFA/trade - Klatt
Robitaille - Conroy - Cammy (if he has a strong camp)/UFA (must have speed and hands)
McEachern - Pirnes - Brown
Cowan - Avery - McCarty or Matt Johnson
Kostopolous/Armstrong/? for scratches and spot duty