I ordered polymer front sights recently and even they had screws, of course they cost $3 each instead of $1.
I asked her three times "the Glock factory night sights have a screw mount right?" And her responce is that they no longer use the stake in.Unless when you shipped yours in they used old stock,trying to get rid of the old style...when I call to order mine this week I will make sure I ask one more time...That's strange....I only had mine done through Glock a month ago, and they are staked. I'm sorry I didn't take the Trigican option..those are definitely screw in type.