Where can I find information on old Fender PA cabinets?

[MayTheFuzzBeWithYou]

There is a Fender 2-12 HF cabinet to be had for a really tempting price.
Aluminum Dust caps - but 4h15 drive each direction keep me from just going there to have a look - and the seller won't open it up for me...

Is there a bullet-proof way to tell which speakers they are from a pic (without grill cloth)? The official Fender serial number forum closed down 8 years or so ago...

I mean, if they are working JBL K120s or something like that, I'd either drive there or send a carrier. For that price.
But these cabs always get sold for a very low price - so either no one is looking on the inside - or they have some rebranded whatever in them...

One ad on FB from years ago claims Jensen, another active ad (selling for a multiple of the price) says they are indeed K120s - and yet another just wrote Fender concert speakers (which might not be the model name - but just a way to tell these were used as a PA).

Any insight?

Thanks for your help!