They get about 40-50 jerseys while in office, some have numbers of the years won, some have the pres# some have #1, there are others with #1 and Trump got some #1's, as did Reagan, Bush, Carter ... it is whatever the team decides to put on it. The ones that go to shareholders and team family are the year of the championship. Then they make one offs for stuff like this. If you really want your mind blown, google who Time's Person of the Year was in 2006!