here's what HTGTH database says about it.
Catcher In The Rye - mentioned in Rolling Stone (Jan 2000)
The Columbine shooting happened in April 1999.
The interview with Rolling Stone that was published in January 2000 was conducted in November 1999.
Brian May recorded guitar for the song sometime in late 1999:
http://www.heretodaygonetohell.com/news/shownews.php?newsid=230Meanwhile, a spokesperson for Guns N' Roses confirmed to MTV News that Queen guitarist Brain May did indeed spend some time recording with Axl Rose late last year. "Brian spent a week with the singer," the spokesperson said. "They recorded several songs worth of material, but we have no idea what's going to end up on the end product."
So you're saying that within a period of seven months Axl produced the entire song?
I don't think so.
The lyrics and song title are directly connected with JD Salinger's book and Mark David Chapman's killing of John Lennon.