Is the "high five" really as new as Wikipedia says?

Yeah, but the high five evolved from the gimme five, clearly.

What few grade schoolers I know seem to be familiar with both. But the fist bump has scores of silly variants, similar in some ways to the variants of “Gimme five” (or the secret handshake) during the 1970s.

Variants of fist bump:

A memorable early 1970’s “Candid Camera” episode featured Muhammad Ali telling a kid, “Gimme five… I would give you thirty, but your face is too dirty”.

A lengthy article about the “high five” from 1981. Most interesting: it might have originated with women volleyball players way back in the 1960s.

I think you mean Respect knuckles.

This makes sense to me; my recollection was it became a thing around then.

Watch Youtube videos of sporting events from the early 1970s. No high fives.

I worked as a PA (Production Assistant) on Hoosiers. Another instruction the crew gave the extras in celebration scenes was not to hold up a single finger in a “we’re number one!” manner. It apparently wasn’t a thing in the 1950’s.

As far as the high five in general, as I recall it was strictly “low fives” for a long time. The high-five was much later.