This page is a census of known examples of the 1899 ½d green stamp (the so-called Widows Weeds) overprinted with the word 'SPECIMEN.' These handstamps are believed to have been for record or presentation purposes only and were not sold to collectors. They were not handstamped in this manner for distribution to the Universal Postal Union; mint stamps being used instead for this purpose.
A Scudder Specimen Type 9 overprint (Kenneth Scudder, Queensland Postage Stamps 1879 to 1912, p. 364) overprint was used for this issue. It was typeset with sans-serif capitals, 15.5 mm long and 1.75 mm high plus a stop at the end. It was applied in red ink on mint gummed issues, wmk 2nd type "Crown Q", perforation 12.5, 13 in around 1899
Examples are also known stamped SPECIMEN after receipt by various UPI countries and colonies, and those for Natal and Tunisia are shown below
CENSUS
NATAL SPECIMEN
Specimen receiving handstamp (sans serif 17.25 x 3.25 mm) in violet by Natal. Seen in Corinphila auctions
Tunisia SPECIMEN