Recently picked up a slightly mismatched pair of slotted Bendix 6080. The pictures weren't all that good, so I didn't catch that the top spacer in one is ceramic whereas in the other it is mica. A picture of the tops showed 6080WB 230 on one and 6080WB 244 on the other, manufactured only 14 weeks apart? So I pulled the trigger.
IMO, these sound extremely good and I am very pleased. However, in the back of my mind, I can't help but think: "different construction = different sound". But as I have only one of each, I have no way to effectively compare them.....
Don't worry, the spacers don't matter sonically. By immense luck I got a dozen of 6080WB's and while there are slight differences in sound, I don't relate that to plates or spacer arrangement. You have two tubes that I'd assume to be the same build. These are the tubes with the usual YY WW (year, week) date code, which have slotted plates of variable shape (chamfered or on-chamfered edges; sometimes solid plates) and copper grid posts. There's a very similar build of which the date code is followed by a three-digit suffix that begins with R and ends with two numbers (e.g. 6246 R35). That build also features slotted plates (often) but steel grid posts instead of copper posts. Its sound is a little different (slightly recessed mids, a tiny little bit thinner overall). And then there's a third build with purple ceramic spacers and solid plates. Similar to the R-suffix, the date code is followed by a three digit "S"-code. It is probably the type which is said to be the "worse" sounding type – I'd say it is just a little gentler. BTW, if the tube was branded for other parties, the R/S codes get lost.
Now, within each of these three (or more) lines, it seems that the spacer arrangement and plate shape varies constantly. It's not even that Bendix used mica spacers from some point, it seems more like a mood thing. Anyway, you have a good pair with the same sound.