O76a-84a (O141a-149a) 1940 ½d-8d Centenary of New Zealand issue, overprinted "Official"^ SG Type O4 ("ff" joined) in pair with normal SG Type O5 overprints in red or black, wmkd NZ and Star Multiple, cplt (8), on the 2½d the variety is the right-hand stamp (pair is row 4, pos 2,3) the others are all top margin vertical pairs (with the variety being row 1, pos 10)
