[burnspbesq]

I recently ordered a RCA clear-top 12AU7 and four Tung-Sol 5687s from Tube Depot.
 
When they arrived, the "RCA" turned out to bear the "United Electron" logo, and the "Tung-Sols" bear the "Lewis & Kaufman" name and a "Los Gatos" logo.
 
Any chance that these are in fact what I thought I had bought?

 

[Spareribs]

It is common for tubes to have a code on it. For example if it has 274, it was made by RCA in the 1950s.  A Tung Sol may have a 322 number on it possibly.

 

[burnspbesq]

Whoever made them, those Lewis & Kaufman 5687s are sounding pretty good working with a short-plate Mullard CV4003 in a Raptor.  Listening to a 96/24 aiff file of "Ella and Louis" right now, and it's really nice.

 

[Spareribs]

Ella and Louis is a one of the great classics. I find that if an amp is well designed, most vintage tubes will sound great so I don't really get too picky on which brands to use and I commonly use rebranded tubes for my stereo and guitar amps. My bedroom tube amp uses Baldwin organ and Dynaco labled tubes which were actually made by RCA and Sylvania respectively- 1959 & 1963. The nice thing about rebranded tubes is that they can be cheap and still sound robust as the expensive names. It's kind of a "best kept secret" in the audio world in a way.