The homie PhillyCustoms confirms to me that this is in fact a reference track for Dre, and that it will be on Detox. DJ Envy also stated that it is Dre's when he played Kells and 50's parts.
Shouts to the NMC.
EDIT: XV says that it's Slim The Mobster rapping, not Bishop Lamont. It's gonna be a long day...
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