No worries, Tony!
JB's are made the same as they ever were. The older JB's sometimes have a unique quality about them, but from a manufacturing standpoint there is no difference whatsoever. I have an old one (JBJ) that I brought in for analysis. I know it's only one, but it was worth the effort. Derek Duncan is assembling a collection of older Duncans to do a more in-depth study, but so far we're finding the same thing. The bobbin dimensions, coil thickness (which makes reference to wire thickness, insulation thickness, perhaps pitch) were all the same. The DC resistance was within spec.
The MAJOR difference was the magnet. The magnet was not only degaussed, but awkwardly degaussed. As you ran along the edge the gauss strength fluctuated quite a bit, and near the treble side was the weakest. This would make the pickup "warmer" and shave off the highs, which is what I heard when I played this pickup. I recharged the magnet, but because it had probably been bounced around in someone's pickup drawer (with other ceramics?) before I got it, the magnet didn't come back 100%, but it was close. The sound was also WAY closer to a new JB out of stock, maybe 95% there. Old JB's can and will have environmentally affected magnets. I can't speak for 30+ years of production, but I can say today's JB's are made the "same" as they were back then.
A coil wound 25 years ago can change a little. The bobbin material, especially if exposed to heat, can shrink back a little, and the coil tension relaxes a little. That can change the sound. You can lose some wax to a hot automobile stay as well.
If you want to shave off some harshness from the JB, do what Seymour does in his Tele-Gib and use it with 250k pots. You can also degauss the magnet, or install an Alnico 4 magnet. I would start there before incurring the expense of a rewind.
If anyone claims they have the "real" recipe for an old JB it has to be snake oil. It doesn't mean Wolfe or someone else can't rewind you a killer sounding pickup that sounds more like what you remember an old JB to sound like, but no one is going to "out-Duncan" Seymour Duncan. The Custom Shop has tons of pickups that they'd call "JB's" because they are all within spitting distance of the stock JB, but maybe they'll do one with a degaussed A5, or Alnico 2. They'll do them over and under-wound, and if you say "I want it to sound like an old one" they'll do it, because it's the same sort of processes as when someone says they want to duplicate the sound of an old P.A.F. The magnet might be charged slightly differently, maybe it's a little more loosely potted, etc.