I definitely noticed that when looking for tyres last month. Sometimes up to £30 extra for tyres with the BMW approved Star on them. For example Asda Tyres (other retailers are available), Conti Sport contact 5's with BMW star in 225/45/R18, £175 each. Conti Sport Contact 5's without the BMW Star, £145 per tyre.
But actually, certainly in BMW's case, the two tyres can be completely different and feel totally different on the car. Whether the extra performance is worth the extra £30 is up to you. I would suggest unless you are using high performance models then its unlikely.