Rose will hit the stage with Slash and Duff MCKagan at this year's (Apr16) Coachella festival in California, but it is not officially known who will be joining the trio.
Reports suggest Axl will fill out the band with current members of GUNS N' ROSES, but fan Mustaine tells The Strombo Show he'd like to see drummer Adler and guitar great Stradlin up there with their old bandmates.
"I don't know that that's going to happen," he said. "I certainly hope that it will, but, you know, in order for it to truly be a Guns N' Roses reunion, you've gotta ask yourself, 'Who's is gonna be there?' I think that it would be terrific if Steven and Izzy was there too, because that would be really, really nostalgic. There's nothing really keeping them from doing it other than personal differences.
"I understand, trust me, I just went through that with the (attempted reunion of the) Rust In Peace (MEGADETH lineup), so sometimes it's not meant to happen."
Meanwhile, Mustaine won't believe the Guns N' Roses reunion is for real until he sees the band onstage, citing Axl's notorious unpredictability.
"I just hope that this thing that happened on (TV show) Jimmy Kimmel the other day isn't an indication of anything that is going to happen with the tour," he added, referencing the rocker's scrapped appearance on U.S. late show Jimmy Kimmel Live! Axl was expected to confirm the reunion rumours on the show earlier this month (Jan16), but he backed out at the last minute.