I think ive beetle seat belt receivers - i'll have to rake through a few boxes; don't know what year your beetle is, but it might be worth putting a pic up of your seat belt 'click in male' bits; it might have been fitted with later seat belts, which were attached to seats eg; mk1/2 golf seats, in the past.... you might be restricted to lap belts in the rear, tho 80s mk2 scirocco have separate 'roll on the reel' middle seat belt arrangements - two point seat belts bacically; two of those might do in the rear of your Bug, tho mk2 sciroccos are hard to find 'for breaking' these days...
