Gambit armors have only been in raids, pillage, and TLCs.
You can use the Brute armors from the FM as a reasonable stand in.
last i looked people needed 30 of these why would you make them limited.
Probably the same reason that it was limited for the Brutes, Lionfish, Everest, Praetorians, and all of the other class fleets over the last 3-4 years.
As for the actual reason, I have no idea. But it is normal and should be expected at this point.
I recycled the 5th ship when I built the flag as it was unnecessary to keep it. Only needed 15 armor each and didn't want to chase points when they weren't needed. Garrison armors are pretty much in events same as conqueror/defender armors. Assault/siege/skirmish usually found in FM or the occasional event if Kix feeling generous.
Before the Flag I built 5 Gambits, 1 with all countermeasures except 1 mort and Brute armours, now when I'm upgrading each Gambit the Anti ship goes back into fleet.
You can use the Brute armors from the FM as a reasonable stand in.
As for the actual reason, I have no idea. But it is normal and should be expected at this point.