In Mark and Darian you have perhaps the two most qualified professionals in the music business working to ensure the accuracy of the 1966-67 studio details as they related to Brian's work at that time. You also have, again, perhaps the two most qualified men on the job who have not only pored over but also love and know down to the most minute detail all of the music and the studio sessions that were to be "recreated" in the film. And they have been working in and around these various facets of the BW-BB's saga for decades.
Consider at this point what a challenging task it could be to essentially rebuild and recreate with a high degree of authenticity a studio room from 50 years ago. First, the original rooms in many cases do not look anything like they did even 20 years ago, in some cases like Gold Star the original room has been gone for 30 years. Second, we do have some pretty detailed still photos and film clips from 1966 showing what it looked like, but most of those little details and trimmings were scrapped and replaced several times over by new designs.
Third, and perhaps most difficult of them all, studios did and do constantly upgrade and replace their existing equipment to modernize the place and market their rooms to potential clients with the latest gear...meaning a large majority of the original gear we now consider classic was at one time considered "obsolete" and out-dated, and therefore either sold off to the highest bidders or in many cases, simply scrapped for pennies on the dollar.
So when you have Mark Linett operating his studio which among rack-fulls of vintage gear has one of the few remaining Bill Putnam modular boards in existence, "rescued" from Western Studio 2, and when you have Darian who was for decades playing perhaps the only custom-built replica of Paul Tanner's original "Electro-Theremin" which itself was a one-of-a-kind custom build, you can pretty much feel comfortable that the details like these would have been placed in the perfect hands for the job.
There were hints and clues given before in this thread and others, but when there is word that anything close to this level of detail and care in presenting the right look and period-correct visuals was the case for the studio scenes, not to mention the use of live musicians - not just actors - playing the session players in the film, the doubts and the nay-saying about certain details if not the "look" of the whole film are soon erased if not laughed off entirely.
Consider at this point what a challenging task it could be to essentially rebuild and recreate with a high degree of authenticity a studio room from 50 years ago. First, the original rooms in many cases do not look anything like they did even 20 years ago, in some cases like Gold Star the original room has been gone for 30 years. Second, we do have some pretty detailed still photos and film clips from 1966 showing what it looked like, but most of those little details and trimmings were scrapped and replaced several times over by new designs.
Third, and perhaps most difficult of them all, studios did and do constantly upgrade and replace their existing equipment to modernize the place and market their rooms to potential clients with the latest gear...meaning a large majority of the original gear we now consider classic was at one time considered "obsolete" and out-dated, and therefore either sold off to the highest bidders or in many cases, simply scrapped for pennies on the dollar.
So when you have Mark Linett operating his studio which among rack-fulls of vintage gear has one of the few remaining Bill Putnam modular boards in existence, "rescued" from Western Studio 2, and when you have Darian who was for decades playing perhaps the only custom-built replica of Paul Tanner's original "Electro-Theremin" which itself was a one-of-a-kind custom build, you can pretty much feel comfortable that the details like these would have been placed in the perfect hands for the job.
There were hints and clues given before in this thread and others, but when there is word that anything close to this level of detail and care in presenting the right look and period-correct visuals was the case for the studio scenes, not to mention the use of live musicians - not just actors - playing the session players in the film, the doubts and the nay-saying about certain details if not the "look" of the whole film are soon erased if not laughed off entirely.

Darian plays a large part in Brian's band and apparently booked ,and rehearsed the musicians playing the wrecking crew in the film, but I doubt he would have had anything to do with the recreation of the studios past the selection of the correct period instruments for the musicians.