Congratulations.....F400640 = Spring 1884. Interesting with that speaker...if it is the original ? Big magnet, probably a 1 1/2" voice coil, but that dustcap would cover a 2" coil, can you see the size of the cone throat? If it sounds good, your in luck, no point in changing it. Lindy reverb cables are definitly new, but hey...no worries, a good price. Any chance of some gutshots to see if all is in order there?