Might depend on the exact year of the amp, but on the couple I've removed that were said to be still stock there were Russian#2 (EH) in V1, V2, and V5, and then standard mesa-branded (JJ?) in the cathode followers V3 and V4.
I'm prety sure that when I bought my f rev recto there were still original tubes Chinese 7025 in preamp and Coke botle str 420 tubes in power amp section...unbeliveable tone which I can't get these days with current production of tubes...