That Carlsbro amp is like likely to have a USA made Accutronics reverb tank in it also, which could be usefull for future projects.
If the amp has a Celestion speaker, it is likely a replacement from the original (unless it's a more modern Carlsbro GLX or something, in which case they might come with them) If it's from the 70's/early 80's, then the original speaker would more likely to have been made by either Fane or Mackenzie, which are great brithish speakers and highly sought after. These were often unbranded or labelled with the Carlsbro name 'Powertone'.
I had alot of discussions with one of the engineers from the Carlsbro factory in the UK, who also used to run (a now defunct) Carlsbro website, where you could date the amps and there were forums, etc.
Another little known fact about Carlsbro, is that they took over production of H&H amps about 2-3 years after that company started. So most H&H amps are technically Carlsbros. One goes for big bucks, the other next to nothing. I have 3 Carlsbro amps from the 70's that i got for under £20 each.
Anyway, good luck with your project!