In the late 70s/early 80s the Japanese guitar companies were trying to match Gibson and Fender in terms of quality and specs. Later on it sort of dropped off a bit. Japanese labour costs rose a lot during the 80s and the guitar companies lost a bit of interest in doing top of the line Gibson copies and in the 80s the hair metal pointy guitars were the ones that were selling big and Fernandes and Kanda (Greco) etc sold hair metal guitars. The Greco late 80s models are not the same as the Greco early 80s models.The guitar factories don't really play a big part in it as they were all pretty good. Like Matsumoku who was mostly known for Arias could match Fujigen in all departments as could many others.
Fernandes used a lot of different guitar factories.
This is info I've gathered from doing detailed comparisons of Burnys with guitars that had known makers. It might not be 100% correct but it is more than just guessing.
Finding things out about Fernandes and what factories they used is probably the hardest of all the Japanese guitars as there are hardly any serials that identify the factories that Fernandes were using so you have to use comparisons of Burnys to other known factory guitars from the same years. Like comparing the wiring channel drilling and the control and pickup cavity routing and the tenon construction and the custom headstock shape of a 1985 Burny and a 1985 Fujigen made Greco or a 1985 Tokai for instance. You can see a lot of the different wiring channel and routing designs at http://www.japanguitars.co.uk/burny%20info.html and at http://www.k4.dion.ne.jp/~yjibika/FernandesRLG90.html
Fernandes had a development link with Matsumoku in the 1980s http://www.daeschler.com/articles/fujigen/ and with Santai/Three Yasushi http://www.santai.jp/guitar/geindex.htm who seem to be just a guitar finishing factory.
Fujigen have made Fernandes/Burnys according to this page http://www.desertrosebanjo.com/consultfull.htm. In the late 1980s/early 1990s there would have been no FujiGen Burnys because FujiGen stopped most of it's set neck production to mainly make bolt on Fender like guitars.
The early 1980s FLG Les Pauls have a centre drilled wiring channel and the only factory I know of that did that was Terada. FujiGen use a wiring channel up the right side of the pickup cavities on the Grecos Orvilles etc and Tokai and others usually use a diagonal wiring channel from the switch to the controls (volume, tone).
Then there are also the Burnys from the late 70s with Tokai serial numbers.
So after doing comparisons of Burny LPs with known factory guitars it looks like this probably happened for the Japanese made Burny LPs.
1970s Burnys were probably made by Terada and generally have a YXXXX (Y=year, XXXX=production number) serial number.
Late 1970s Burnys were probably made by Tokai and have Tokai serial numbers.
Early 1980s Burnys were probably made by Terada and generally have a YXXXX (Y=year, XXXX=production number) serial number.
The early 1980s FLG-240 FLG-150 FLG-90 and FSA-80 Semi Acoustic models with nitro finishes were probably made by Terada.
Early 1980s to late 1980s Burnys were probably made by Matsumoku and FujiGen with no serial numbers. Matsumoku made most of the RLG models including the RLG-150, RLG-120, RLG-90 models and FujiGen made most of the RLC models.
Some of these Burny RLGs have the Matsumoku bolt tenon that was also used on the Matsumoku made Arias and some like the RLG-150, RLG-120, RLG-90 Burny models http://www.k4.dion.ne.jp/~yjibika/FernandesRLG90.html have a Gibson like diagonal wiring channel (just under the Maple top) that's very similar to some Matsumoku Arias and that's different to the Tokai diagonal wiring channel design that goes through the Mahogany Body and doesn't go just under the Maple top.
From the late 1980s not many Burnys would have been made by FujiGen because of FujiGen's decision to stop a lot of it's set neck production. Also Matsumoku went out of business in 1987 which could be why the RLG-150, RLG-120, RLG-90 models stop around this time.
Early 1990s up to mid 1990s Burnys were probably made by FujiGen.
Current Japanese made Burnys are probably made by Tokai.
The Burny Acoustics up to 1982 were probably made by Hayashi Gakki and after 1982 by Headway.