555: The Name's the Game

Explanation
In the original comic, Charlie Brown's reaction to the names on Lucy's list is "Nobody's named Bill anymore..." See 430: "Rerun" isn't much better, which points out that the names in the comic don't seem that unusual today. Here, the joke is traded out with Charlie Brown asking if those are the players' first or last names. Wiktionary shows that every name on the list is both a given name and a surname, so they could be either given the lack of context.

The author writes
It struck me as I read the original comic that I couldn't actually figure out if those were supposed to be first names or last names; for most of those I could think of a person with that last name more easily than (or, at least, nearly as easily as) of a person with that first name. (The exceptions were Justin, which is mostly a first name; Hunter, which is too strongly associated with Biden Jr.; and Travis, where I couldn't think of either.)

As it happens, it's only the last panel that provides the "first names" explanation; well, that and if they were last names there wouldn't have been much of a joke. But if we ignore the last panel, both first names and last names would fit the context fairly well. So it makes sense for Charlie to ask.

(Text mostly copy-pasted from elsewhere in the strip, though I had to copy the question mark from the previous day's strip, since this one didn't have one to copy.)

Original Peanuts strip: 1997-07-19.

Transcript
{Lucy and Charlie Brown are standing on the pitcher's mound during a baseball game} Lucy: Look, I found a list of the players on the other team.. Lucy: {reading from the list} "Clay, Blake, Morgan, Travis, Trent, Hunter.." Lucy: {reading from the list} "Bailey, Madison, Taylor and Justin" Charlie Brown: Are those their first or last names?