On these Hondas, it's a single piece exhaust manifold and cat. Why, I don't know, but it is. That's why I said I replaced my mani-cat. May as well, too, since the OEM manifold is prone to cracking. That's why I replaced mine, not for the cat.
Correction: Looks like the 92-95 Civics use a 2 piece setup. You still have to get a correct-spec unit that bolts up to the manifold, though. Big flat flange on the top, slanted flange at the bottom.
$461 for oem, but I'm finding aftermarket units for about 200. You have to sift through a lot of "universal" parts to find the right one.