Hmm, well, the markings do correspond with what is expected according to the latest On Semi datasheet (Fairchild now being part of them), the "WK52" being factory, wafer, and week number. But, the lines are in the wrong order - it supposedly should be "BS170" on the first line. Older Fairchild datasheet doesn't give any info on package markings, unfortunately.
I'd have a search on LCSC and compare pictures. That'll probably tell you if they're actually a different brand.