only have one of this
http://img4.imagetitan.com/img.php?image=23_ge1.jpg
and two that show white fog
http://img4.imagetitan.com/img4/small/23/23_ge2.jpg

any idea on if/how a complete quad can be assembled? Any use in the "good" one, assume the fogged ones goners? Measure it and ask the usual outlet for a "match"?
Obviously one of those tubes is a GE that's the brand. I am not sure on the other tube. If you're trying to assemble a matched quad you need to get them tested and see how closely their parameters match.
I believe the logo on the first one is  Shuguang. Because they are at least 20 years old I wonder how they compare to a current batch?
I wouldn't bother. A new set of 4 matched 6550/KT88 run $120-$200 JJ/Tung Sol/Gold Lion. 
I hear you....but I hate for stuff going to waste.
would agree with @jond , get them tested before you do anything. no point in using your amp as a tube tester. a 20 yr old Shuguang is going to be good for the trash,  likely not good for normal use......that shuguang was made back when  you had a 50/50 chance a new shuguang would go super nova on you on power up. 20 year old chinese tubes are well known for their high failure rate, especially in something that runs high B+
Wow, easy here...I did leave out that the Shuguang quad do service well (I was just looking for the brand so I could ask if there is tubes with comparable characteristics) ..I did buy the quad of Shuguang as matched pairs from a reputable source and have probably put 100 hours on them, half of it in 2002 and the other half last year each time in a car tube amp of Italian origin.
No complaints, was only looking to get a 2nd matching quad.

The 3 GEs were in it before, obviously not able to run it on "three" legs I went for the (then) costs of a matched quad. Kept the GE tubes...and now realise that the two with the white fogging probably have air inside and are of no further use...and the third one may or may not be worthwhile but would require matching with the "to be acquired" tubes.