My amp tech friend is working on a Silver Face Fender Twin Reverb that has Celestions in it. The guy told my amp tech friend he ordered the amp with them new and my tech friend asked me about this as he knows I am online at the amp sites ect and knows I built the 5e3 I built and now the 5f4. Anyway I looked at the Fender Amp Field Guide and I do not see any model Twin having Celestion speakers? Did Fender at one time offer them in the SF Twin as a option and if so what years. Like I said I seen Oxford, Utah, Rolad, or Guass and EV mentioned and I know you could get JBLs Special order and this web page pretty much covers the Fender speakers
http://www.tcguitar.com/articles/gagliano_pt3.html
I do not see Celestion speakers anywhere listed I think the guy was giving my tech A BS story. I saw the amp and it is a Silverface Twin and my tech mentioned he knew it was an older one as the diodes in the rectifier circuit were an older type of diode with a different shape I forget what he said but he recognised them as an older style diode.