As long as you can get all the fittings to turn out of their threads and reassemble the whole thing, I'd save it and do the work. A replacement one from Groco will be about $250.
But if anything's frozen-- especially if you are not the first guy to find that it is-- I'd be wary. Frozen fittings invariably tell tales of other attempts to bang them loose. You don't know what's gone on there-- if they're frozen, there's a reason, and it tends to lead one down the path of discovery to corrosion, brittleness, and metal fatigue. The intake strainer is one of the most vital parts of the boat, not just for what it does but for how vulnerable a point it is if it's compromised. Use heat (not too much), gentle persuasion, and patience. When reassembling, bronze-wool all the threads, polish towards golden prettiness, and use plenty of anti-seize.
BTW-- if you need to replace it, check out Great Lakes Skipper online. They liquidate discontinued boatbuilders' inventory and have quality new parts for pennies on the dollar. They'd have one of these.