Back to the original question, based on the information provided, I would give the W to RP #1.
All these stats are great, but the scorer needs to decide before he closes up the book at the end of the game. I'd probably nibble on my pencil for a minute or two before deciding.
The worth of W/L for relief pitchers is dubious at best and agree with all the discussion. I don't think we'll be seeing this statistic go away, because it is somewhat meaningful over a starter's career (starters with 300 wins and HOF). For relievers, I've seen guys with a few wins that were achieved by blowing the save and then having his team come back after he's gone.