The pipe is part of a collection called The White Spot Collection, made of limited series of shapes replicated from the factory design charts of the 1920's. Yours is the number 0363 (I have the number 0255). The R means the shape Pot, tapered bit, showed for the first time in Dunhill catalogue in 1928 ( I have also a R, Shell briar, from 1966). So all good. Happy smoke!