question about the movie

Rating: 10/10 (24 March 2002)

I have already commented about this movie - brilliant and artistic - but I have a question about it. This review contains MAJOR SPOILERS. I repeat, MAJOR SPOILERS. DO NOT READ IF YOU HAVE NOT SEEN THE MOVIE.
If you have any ideas about this question, please write me a private message. On viewing the movie the second time, I noticed that Natalie at one point noticed an empty spot on Leonard's chest and asked what it was for. Leonard said something like, "I guess for when I've done it." Then later, towards the very end, I noticed the "I did it" tattoo on his chest, around that same spot, in a brief shot with his wife.
I assumed it meant that Leonard had already killed the man who raped his wife (as Teddy had told him), but I checked the trivia section and the person who posted the trivia seemed to think that "I did it" referred to Leonard killing his wife. It's not that big of a plot point, but I'm just wondering, and very curious.
Any ideas? If so, send me a message.