[Superscope]

Now there's a few Numbers to get ones Head around!
Although we would need the Meter's Serial Number (Date) to make more sense of them.

Can we have the Matching Serial Numbers to go with the NATO Numbers?

Most of the Numbers are familiar, but there are a few new ones.
Can I confirm that the 6625-99-949-1853 you have is printed on the 9sx itself, as you put one reference to it under the Case Numbers. I've not seen this number before.
Can't see the same number being on a Case and a Meter, but hey, who knows!

6625-99-949-1823 & 6625-99-949-1824 are new to me as well, but they are very close to the Military 7x & 8x NATO Numbers, so it is possible they may be the correct Cases for those Models. (Only a Guess at this Stage).

6625-99-949-1977 is also a New number. No ideas with this one yet.

Also which 9sx's have an ID stamp on the Front Panal?
I'm guessing it will be the ones with "Multimeter type 12889 5QP/17447 on the Scaleplate.

Do any of the later 6625-99-105-7050 (9sx Scaleplate) Meters have an ID Stamp on the front?

I have only ever seen one Meter where the Model ID looks to have fallen off. Actually on Ebay. Can't imagine it happens very often, but for sure it can.
That would leave a very clear Hole in the Front Panel.
All of the blank ID stamps seem to be part of the Panel molding, so they probably can't fall out.

Based on the limited Data I have, the original 9sx did have an ID Stamp on the Front.
The Scaleplate had "Multimeter type 12889 5QP/17447" and no NSN.

Later versions had no mention of 9sx at all, the ID stamp is Blank, and the NSN is printed on the Scaleplate. see post 1451 where this is discussed together with other differences.

I do have a 9sx Operations Manual (essentially the same as the Test Set Multirange No 1 Manual, but in the slightly older Size format), so whether the 9sx was marketed under it's own Name, who knows.

I get the feeling, the 9sx was probably in production for the Uk Military before NATO picked up on it, hence earlier Meters don't have a NATO Number.

Ian