"ZA.0374 Antenna Rods 'A', Pegs" is the British version, and goes a long way back.
They're a general purpose anchor pin from the 1930's and may well still be in service today. The ones I have are painted green and either steel or some light alloy (I think). Originally issued with the 34-ft sectional mast (and its predecessors), also used as stay pins with the Canadian telescopic (34-ft and 20-ft) masts, the post-WW2 27-ft (larkspur-era) telescopic mast (only to anchor the flat baseplate on soft ground, the stays used 18-in steel angle pickets), the Racal MA675 and later (PU-8?) masts, again only for the baseplate. No doubt used for other purposes - the Aerial Base No.25 could be removed from the vehicle roof in some installations and pegged to the ground as a remote aerial for the C11/R210 station.
I suspect the specification only laid down the dimensions and material, and the manufacturers used whatever suited them. (The light alloy ones seem like a lost cause, since the aerial kit was a heavy (in the case of the 27-ft mast,
very heavy) item, and shaving a few ounces off the weight of the rigging kit seems pointless - if they were diecast it might have been for mass production, of course.)
They have always struck me as being far too small to be used as pegs for guying the 34-ft steel mast anyway. They might work on hard ground (or grassland), but would be a lost cause in a desert. The 18" steel angle pickets for the 27-ft mast were a lot better, but those, the enormous base spike, and 4-lb hammer resulted in a rigging kit that weighed more than the actual mast!
Chris.