if the ears are grey it's not a leu. Most likely its a min mo ( minimally marked mosaic )
you can also look for any other non white marks and non white whiskers, those are markers for mo's. One dark whisker is enough to make a glider a min mo instead of a leu. Which makes it difficult for some to see the difference at first.
the leu het would have to prove out. Which can only happen if the male breeds and the pair produce a leu then his leu het would be proven. Until it's proven you only have the percentage of leu het from his lines that may or may not prove out depending how he's paired.
Het is a physical trait in a line that is not showing physically on the glider itself but the glider can potentially produce it depending on the pairing and the mates genes/hets. I hope I Said that correctly genes and hets aren't my strongest suite.
Really the only way to know for sure what his hets are without breeding them is to look at their lineage/lines. Which you'd want to do before breeding them anyway.
Not sure if this will help any but I had a white face blonde male with leu het paired with a leu and they produced 2 silver belle plats and a standard gray. So he proved out plat.
My friend bred his brother who was a mo and proved out mo's they were born at the same time/ had the same parents. Though I can't think what the parents were I think it was a mo with leu het and a leu
IF I made any mistakes in my explanations feel free to correct me as I said explaining the gene het side of things are not my strongest area.