Flyers often show prototype or sample versions of the game, and often they changed minor details by the time they went into production, or even after production started. On the "after production" ones, this creates two versions of the same game. IPDB will usually mention these latter situations in the "Notes" section, and IPSND lists these under the "Game Traits" tab.

I don't see that difference on either of those sites, so it was probably only on the prototype and/or sample versions of this game that they used the baseball caps.

Sean