Rod wrote:
Going the route "back to the future", I dug out my
old 1969 Gibbons simplified, and yes, starts at NC1
which thus coincides with 1990 Gibbons as NC283,
so Gibbons must have had a major re-number under
D: North China

I accept that simplified is just the boy scouts catalogue,
but will have to do until I find a specialised at auction.

Just as a FYI , there was a gap between NC59 and NC 67
so my Mao stamp was not in either catalogue, probably as it had
little , if any usage.
Cheers.

I had a look at the used prices in my 27 year-old catalogue, and I see
that all the used prices are higher than mint, though not remarkably
(usually around 50%), except for the $500 imperf, which is priced the
same mint and used. This set is the second last listed for the
Shansi-Chahar-Hopei area (there was another $500 in a different design
as the last from the area). Perhaps Gibbons had doubts about their
genuineness, or listed them somewhere else in the maze.