I had a quick look through this thread and found some stuff to comment on. If I missed something and managed to add something already established, I'm sorry. I'll give it a detailed read-through later and see if I missed something.
First off, the neck-stamp is a date, Jan 23 1980 in this case. The same format is used for a long time (I believe?) into the Revival era. To keep things interesting, the date is sometimes reversed, from right to left, with the year given in the Japanese Imperial calendar format (53 = Showa 53 = 53rd year of Hirohitos reign = 1978 etc). I've had a FMT-40 stone logo Mustang copy with that date format - which kept me awake at night for a while.
So far, I've seen no other manufacturer using the fifth hole through the neck pocket for what appears to be paint shop handling purposes. It's quite specific, very coarse on the outside (i e under the neckplate) and to my mind a good manufacturer tell. I very much doubt that they would change the paint shop working procedures for a specific customer, especially if the result is invisible in the finished product. I've had several of Aria Pro IIs final generation of Matsu-made Strat copies from the same period, and they didn't have the 5th hole.
That Kawai made the bulk of Fernandes Fender copies from the spaghetti logo era and through the 80's has been accepted as fact for a while now, afaik. We all know how dangerous that can be, but personally I'm inclined to accept it. For one thing, there's an interesting 1990's interview with Fender's Dan Smith, in which he talks about the run-up to the formation of Fender Japan, and he states that Fender "talked to Kawai, who were making guitars for Fernandes", something that should have happened during 1981. I reckon he would know, and it's about as solid a piece of evidence I've seen so far, in lieu of official documentation. Since Fernandes Fender copies had the fifth hole at that time and for several years afterwards, I would assume that they remained with Kawai for at least most of the 80s.
The interview is here, and a good read all around:
Interview: Fender Visionary Dan Smith on How to Turn Around a Faltering Guitar Brand | Bacon's Archive
Re: the L5002T pickups: they're copies of Schecter F500Ts, as found in the Schecter "Dream Machine" Strats, which the FST-90 and -150 copied. They're tappable pickups with two coils, one inside the other. I have a couple of them, I've never had them installed in anything, but they measure around 6k with one coil and just over 12k with both.
Greco had a similar pickup (though hotter, 9k/16k), the SE-1T. I have two undocumented pre-JV 1982 SE-600s (still with model stickers) with them and the same control setup as the FSTs, i e with two push-pull pots, volume and tone. I haven't played them in a while, but as i recall, one pot kicks in the second coil in the bridge and neck pickups while the second one activates the middle pickups when the five-way hasn't already. Complex? Yeah, like a combination lock, basically, 15 tones in total. And weird, there's a setting when both coils in the bridge pickup and one coil in the middle pickup becomes the world's muddiest 23k humbucker. Interesting stuff.
As far as I know, Schecter used the same setup, so I would assume that the FSTs did too. Not sure, though.
