"The loading screen border trim you earn will display when playing in the ranked game type you earned it in. For other queues: In 5s normal or bot games the highest of your ranked 5s or solo / duo queue will be displayed. In 3s normal and bot games, borders earned from your ranked 3s will be displayed. For ARAM , custom, and dominion games, the highest of any ranked queue will be displayed. So, for example, if you earn Diamond in solo queue and Silver in Twisted Treeline, you will display a Diamond loading border in solo queue and unranked games, but you will display a Silver border in ranked Twisted Treeline.
Regardless of game mode the border trim will only be displayed to your allies, as we still want to be very careful about influencing perceptions around the fairness of the matchup before the game begins.
So your silver border will be displayed in normals too if it is higher than your solo queue rank. Will be shown in dom, aram and custom games. Same deal.