For those not yet familiar with older Dunhill stamping conventions, the nomenclature of vintage pieces like this cause just so much confusion. This is a good guess, at best, and judging by what stamping methods are used, a post-1950s, but pre-1975 briar. The "F/T" simply denotes a fishtail bit, the "R" a Root Briar finish, the "FET" is part of the old letter shape designations - in this case a Prince (well, a Prince stummel, at least), and the "4" the pipe's Group size. Oh! Almost forgot, this beauty is unsmoked.
R. 'Bear' Graves