If your linestage is a MKIIa, there's a MP of 12au7 and MP 6922. From my experience, the 12au7 position is as sensitive to tube rolling as 6922.
One has to realize in order for a company to support a product line, they need a large inventory of tubes so are not going to use rare NOS as stock ... with the exception to Shindo. Also from what I've read and heard, most companies expect customers to roll tubes so why bother using rare NOS as stock.
Currently I'm using Pass XA160.5 but looking to purchase a tube amp soon. Considering Music Reference RM300 monos and waiting for Roger's test results on KT120s before making a final decision.