I don't own Necroticism yet, James. I don't know much about it. I've just heard clips off that album via Amazon.com. My Carcass world currently revolves around 'Heartwork' and 'Swansong' and I know he ain't there on Swansong.
As for Heartwork, I do see Mike's name on the album credits.
For some inexplicable reason, I thought that perhaps the so called Guitar World article is true and that perhaps all was recorded and Mike became part of the official lineup afterwards. Like I said, I don't own Necrotism, so I never really looked back from Heartwork all that much. This is the cause of my illogical statement/conclusion, and not because I don't purchase music.
Fucking hell.