License an Abandonware Game?

WolverineOfLove writes: I'm recreating a 1980s abandonware game with copyrights that have been seemingly unused for the past 18 years. The situation is detailed in a Slashdot Journal entry I just wrote, but in short: Is it worth dealing with all the copyrights and paying money if I want to recreate an abandonware title as an open source game? I know there are legal implications to certain decisions I might make, but there is a real possibility that this game's copyright holder will do nothing with the rights, and I'd much prefer preserving it for others than letting it fade away.