I just got this 4.6x30 round that I believe is an AP loading. Am I correct, and how scarce are these? Is there anything significant or interesting about the headstamp?

That should be the DM11 AP.

Made in 2004 and sowith predating the adopted versions of the Bundeswehr I think.

Maybe someone else can provide more info.

Jon, here is some data published by RUAG Ammotec in 2004. There is also a variation loaded with a shorter bullet (identical on the outside).

Is the “G 1135” a case lot number?

G is the month (July) and the 1135 is the lot number.

Same as with the lot numbers the US is using today.
The first lot numbers of this style I have seen with the German military and wonder now who invented this style and if it became NATO standard maybe.

So is that the lot number for the case manufacture or the loaded cartridges? It doesn’t seem to make sense to me that they would use a new bunter for each ammo lot.

The lot applies to the case only as usual. Inevitably the bunter will become obsolete after the lot is done.

It is my understanding that the lot number is a cartridge lot, not a case lot. This is a) my observation and b) the way the regulations, as I know them, prescribe it.

The numbering after the month-letter is left to the manufacturer. While MEN seems to use more or less consecutive numbering, DAG uses (at least for pistol ammunition) the first two digits for identifying the cartridge type (for example 07 and 08 for 9 mm variants) and the last two for consecutive numbering.

As per German regulations the hs applies only to the case. It would be a new thing if the hs would refer to the whole cartridge.