I bought some of those awhile back, probably 3 years ago from an ebay vendor and I don't have the vendor info in front of me. By the looks of the picture they look genuine. MrSubaru1387 did a video on YT about the knock off JDM filters...
The knockoffs will have a sticker placed on the box, genuine JDM filters will have that part# etc etc printed on the box.
The knockoffs will have a line of glue holding the flap shut, genuine JDM filters will have 9-12 little blobs of glue holding the flap down.
Hope this helps, check out Mr Subaru1387, I linked it for ya