[Microphones] Is this a Kellogg?

[MUCHSTUFF]

Is this microphone a Kellogg?
The only marking that I can find is "1730"
What is the model number?
The case is not that of a Kellogg 501, but the best I can tell
    is that the 2 button element inside looks like the one inside
    a 501.
Did the 2 button Kellogg elements have any markings 
    other than a serial numner?
Could this be a Kellogg element in a non Kellogg case?

http://www.muchstuff.com/1-21-10/kel.JPG
http://www.muchstuff.com/1-21-10/kel2.JPG

Gene Rippen, WB6SZS