actually that is a b18b out of a 94-95 LS. you can tell by the valve cover.
90-93 LS valve covers looked exactly the same, only where it says "Honda Motor Corp" it has the "H" logo above it.
in 94, they kept the same style, but removed the H logo.
and in 96 they changed the appearance of the valve cover completely, to a much nicer looking cover. not blocky looking lol.
hope that helps.
i agree that 3000 is a little cheap for a 98. to be safe, i'd just steer away from it. BUT then again, this also could be a great deal, and if you dont buy it, you'll feel bad for not getting it, because that would be the quickest little 98 civic you'd ever get for 3000. its up to you. very difficult decision indeed.