Yeah I've never seen a fake replica before. As Billsfan says, they'd be too much effort to make for the money they'd be able to charge.
Real authentics are £150, so they can sew on (badly) some cheap numbers and list them for £30 to sucker in some people who don't know/don't care (coz theys cheap innit) that they're buying a fake. Thus making about £29.50 profit.
But to make a replica appeal to the same sort of buyer, they'd have to list them at about a fiver and make only a few quid profit.