In the Netflix Umbrella Academy S2, why does "adult Five" know Luther's name?

I have always assumed that Five doesn’t have another name because he jumped into the apocalyptic future before robot mom gave the other kids names (One = Luther, Two = Diego, etc).

But in S2 of the Netflix show, when Luther and Five confront "adult Five" in the Irish pub, he knows Luther’s name. The interaction goes, roughly:

Luther: "It’s me, Number One."

Adult Five: "…Luther?"

This would imply that the kids got those names before Five jumped. Is there anything about this in the comics?

I can see why Five might not feel an attachment to his "mom-given" name if it was a fairly recent acquisition before jumping, but 1) wouldn’t the others use it for him? and 2) wouldn’t he be similarly un-attached to Luther’s name and instead just call him "One"?