Kenya Uganda Tanganyika SG 17/31 Specimen 1904-07 set to 10r watermark MCA with unlisted overprint

1904-07 set of 14 to 10r grey and ultramarine, wmk MCA, blocks of 4, opt (½a to 8a) or handstamped (1r to 10r) 'SPECIMEN', unmounted o.g. Believed to have been prepared for presentation purposes, possibly in connection with the change of watermark from CA to MCA the 1r to 10r have the standard local handstamp applied diagonally in violet (Samuel type K3 - previously unrecorded prior to 1912) while the ½a to 8a have a type-set serifed overprint and are unrecorded thus. The 2r and 3r blocks lightly folded otherwise fine and very rare. [N.B. The overprint on the ½a to 8a blocks is similar to that found on a recently disovered Leeward Islands 1890 set from the Tunisian post office archive, but is slightly larger at 15 x 1.75mm.]