@JRp-90 The following is to the best of my knowledge.
The company's initials are BH which is BooHeung Precision Machinery based in South Korea. A BHK sticker indicates made in Korea and BHC sticker indicates made in China. Many have the "BH" logo die-impressed in the baseplate. They are also marketed as "Hotch" pickups, which might be the H in BH. They *might* be marketed as Belcat pickups, their humbuckers having "BH" in the part number. BH makes or markets active humbuckers under the Rockfield brand.
They're wax potted, some have 4-conductor wiring to use split-coil switching, and Fender says they have alnico magnets, but doesn't say what type.
Some folks like them, but at a typical 12.5K to 15.5K Ohms they are IMO dark, muddy, blasters with poor definition because the treble is so minimal.
I had a Blacktop Strat with the same 12.5K neck and 13.5K bridge humbuckers and found them impossible to tame enough to get an articulate, clean tone. Turn down the amp gain enough and the tone was crud. Turn down the guitar's volume control enough and the tone was crud.
The ones you have aren't unique to the Blacktops and have been used in other models. For example, the early Fender Chris Schiflett Telecaster model used one in the neck position. BH pickups can be found in various Epiphone, Samick, Tokai, and Washburn guitars, and the import lines of Gretch and Guild.Some of the "Duncan Designed" humbuckers have the same BHK stickers.
