I suppose the question could be restated: Has Keen always been a +1 enhancement in 3e and 3.5e?
I've been playing this game for some years now, as has another player who also frequently runs the game in a very by-the-book manner.
Yet, we were both surprised to see Keen as a +1 enhancement in my July 2003 printing of the DMG. We have been playing it as a +2 for so long, but cannot possibly fathom why.
I suppose it's more likely that two people are simply remembering wrong - but I also have no access to D&D 3e material, and perhaps some features of the older system crept into our games, so . . . At some point during the life of D&D 3e and its revision, did Keen's cost change?