Audio Research Reference 3 Bypass Caps Question

I couldn't get the photo to show.  The silver caps with yellow ends are on the same board and side as the 4 tubes but on the opposite end of the 4 tubes.  These are the ones I am missing. 

It appears that you are correct, but IMO/IME bypassing coupling caps isn't a good idea. Different caps have different extended series resistance, they have different dielectric constants (even if made from the same material) and as a result the signal gets smeared if the bypass is present. Part of this is that the coupling cap at the output is directly involved with the output impedance of the preamp (being a series impedance with it). IOW when it comes to coupling caps, you give it your best shot with the best cap you can come up with. It won't be perfect (nothing ever is); if you want to move away even further from perfect. then go ahead and use the bypass.

Bottom line- I bet it sounds better on a good system without the bypasses.

Thank you!  I really appreciate the info and feel better about my not having an updated model.  Since it had been working fine for 13 years I had been wondering if it would be worth having it updated. 
BTW Audio Research told me they no longer offer this mod so I would have had to find someone else to do it anyway.