Like machine said , most non conventional SF units have a very wide variety of options when it comes to gear and weapons. Ive seen SF guys in country with sigs/glocks/ and H&K’s.
What you an machinedrummer said is common knowledge but they do purchase specific pistols for the team and Sig has been advertising their pistols being used by SEALS for some time. Sounds as if Glock is replacing the SEALS Sigs.
Sig advertises that because SEAL candidates are issued the Sig during training... That doesn't mean they all actually choose to carry it.
Wasn't it not too long back the government went through a very long and costly qualifying process with all the modern handgun producers to pick this armorer. If I remember right the firearm had to meet a very high threshold for durability and accuracy. What happened?