Those boxes are so cool.
Seems like you got yourself a bargain there. From what you describe with the resolution boost and all round performance it sounds like there might be at least some common ground between the new ones and your NOS - but its hard to say without a head-to-head and from the pics I think your ones might have longer plates. I always tend to think the NOS would sound better and have more magic!
I haven't noticed the gain difference with the Tung Sol re-issues i've heard - i'm not sure of the spec differences between a 6189/12AU7WA and the regular 12AU7 other than that they are military grade with some construction differences to withstand rougher treatment.
Hope you continue to enjoy them,
I've not changed back to my mullards yet these are really sounding nice, I've been using the wa7 with the gain selector set to low I switched it to high last night and they seemed to jump to life a big difference, overall SQ is much improved, very deep bass I love it and yes these were the best tube bargain I've gotten so far 6.40 ea.Lol..