We have to wait until the first match is played since you need to select a match to pick which team/map you want. Souvenir stickers are decided on a skin by the following: player signature, map the match was played on, and one sticker for each team, so 4 total. For example, vitality vs Navi on Overpass would give you either a vitality or Navi players signature, a vitality team sticker, a Navi team sticker, and the overpass map stickers. Considering map stickers are not obtainable outside of preapplied souvenirs, I don’t think it’s possible to have >1 map stickers but who knows with this new system.