What a nice assortment :)
The G in a triangle is Grinnell's mark, partly company mark, and perhaps also casting mark, as they had their own sand foundry for making pipe fittings, and I have heard persistent rumors they were making other things there as well. (About the time I had access to what was left of the local foundry here, someone took all the mahogany sand patterns home and burned them in the wood stove :(
They made Grinnell fittings, gem valves, grinnell hangers, etc. The G is for "Gem" (Grinnell's sprinkler manufacturung company.)
Gem us part of Tyco, Grinnell fittings is now Anvil.
Star was bought out by Central, which was in turn bought by Tyco. Globe Sprinkler is still alive and kicking. Automatic sprinkler isn't around, but their owner Chemetron is.
I have a lot of old sprinklers, if you want I can see if I have any that went with those. I also have a lot of old, and many new head wrenches.
Sprinkler systems are supposed to have a spare stock of sprinkler heads and wrenches in a spare head box, located near the main feed riser in a building.
By the way, unlike in the movies, sprinklers are each operated by heat - usually only a few operate. There is no way to turn them all on. Sprinkler systems are not even designed to extinguish fires, except for some recent types for certain warehouses.
Chilly