The bar is not set at "collector grade" height, however.
They allow shank leveling and tape-thickness-height stem face overlap, for example.
Either of which screams replacement.
They also allow an un-radiused button/bite zone convergence angle, a too-pointed button face profile, an improperly radiused funnel & slot, and (if applicable) the ABSENCE of the 45-degree tenon/stem face connection found on pre-1970's pipes.
All instant replacement giveaways.
In short, the old phrase "close enough for government work" applies.
Fine for tobacco access device users who happen to like Dunhills and are happy with an 80% or so match---which is doubtless the majority of Dunhill smokers---but NOT the sort of workmanship that retains the value of a collectable.
I'm mentioning it because the "Dunhill Approved Repair Shop" phrase has caused many owners to unwittingly submit their pipes for destruction in collectable value terms (via shank leveling), and/or end up with a stem they are disappointed with.