GG: First Releases, First Authorized Releases and the Vault !

[Charlie Siffermann <charlie@swlink.net>]

Dear f-minor,

As I continue to scoop up my share (or more) of the GG discography, I
have taken a moment to wonder...
...I have seen many First Releases and First Authorized Releases of his
music.  
Does anyone know how or why the GG estate would decide to first issue a
GG recording?  
(I would like facts if possible, but theories or guesses are fine!)  

As a corollary to that, 
How do they decide what not to issue?  
For example, the Brahms Concerto with Leonard Bernstein. 

I also wonder does anyone have a list of recordings GG made that are
currently unavailible?  

I would appreciate any thoughts (especially from those with better
things to do than complain about our group).

All the Best,
Yours,
Charlie