Indeed after about an hour of searching, I found it.
I’ll happily accept a gratuity
It is indeed a stock part, would definitely fit a prefl jdm bumper.
To which this one is attached.
https://page.auctions.yahoo.co.jp/jp/auction/m311188365How I found it: my usual approach of translating “front aero” into Japanese and searching on import monster with BP BL added... Did not work.
So I searched “front bp bl” in body parts, also on import monster, and looked at all the hits on bumper extensions that looked similar or desirable.
One of these hits had a factory part number, but not for that particular item...
I google picture searched the part number and it lead to a link to a reseller: still available new and in your paint code!
http://jsound.info/%E3%83%AC%E3%82%AC%E ... %E3%83%BC/Another hit came up with a catch all bp bl front aero page on yahoo japan and that’s where I found the item above
https://auctions.yahoo.co.jp/search/sea ... 084005255/Still no part number but that’s a search for another day