Only the sizer die is carbide in most if not all die sets. The exception is the Lee Pistol Factory Crimp Die (FCD) has a carbide sizer ring at the base to resize loaded cases to meet specs for the given calibre. This is so if you made a mistake in loading the rounds it will resize the cartridge with this ring (also in the top of the FCD is the normal taper crimp for crimping the bullet) as well as crimping so it performs two actions at once.
I own the Lee 4 dies .45 Colt set, Carbide sizer, expander, seater, FCD and none of the dies have the word "Carbide" stamped anywhere on them.
There is however clearly a carbide ring inside the base of the sizing die and the FCD.
Although there are still steel pistol sizer dies, most sizer dies for straight wall pistol cartridges are carbide in the last 25-30 years.