I just bought a vintage style stratocaster neck from Hosco. It costs a Little over $150 and to my surprice all the frets had a thick layer of lacquer on them. shoulden one expect for that Price, that the frets was cleaned and polished?
Fender doesn't do that for their high priced American guitars. Warmoth says on their site that they leave the finish on the frets. I would not expect Hosco to clean it off. I do agree that the coating in your photo looks exceptionally thick though. Maybe send the photo to Hosco and ask if this looks normal to them.
This happens even on expensive USA Fender Strats with maple neck/fretboard.... 100% normal. the neck is finished after frets are put on. Just have to polish it off or just play it and it will naturally wear off....
