I'd say they are genuine. I was doing fifteens before 18's. I seem to remember routing out the grill frame from solid with those round internal corners. I've forgotten half of what I've done in the past.
If someone can get them cheap enough with those speakers in them, it would be a good little system with 2 per side with a mid and top above.
Tony, you made 4 of these for me back in the dim and distant past (check the avatar - those were the actual boxes). Loved 'em, but one got stolen. We eventually sold them on for no where near that sum. £550 each is a bit much!
It's certainly a buyers market today. When it comes value, sometimes cost bares no resemblance to what you are getting performance wise. Everyone tries to buy cheap, which is only good on one side. It's also the reason why not many people make much money in this business.