[Dave Moll]

What's fitted inside the speaker housing of the later one is a replacement from (if I recall) a transistor radio, as the one it came with was O/C.

What, in particular, were you wanting me to look for?

I don't know what the preset is for, either, but there is one at the rear of the earlier tranny version, and also one inside the valve unit (though only accessible by removing the back cover).