Yes, the mosaic or atlas map look. A Monoembryonic seed usually has two segments of seed divided directly down the middle. Sometimes Monoembryonic seeds will have segments that are slightly deformed or the segments are offset, giving it the appearance that it is Polyembryonic when it’s actually Monoembryonic.
Aside from the mosaic pattern, I look for multiple root stubs which normally start pushing before the vegetative sprout. Simply remove the seed from the husk and wrap it in a slightly moist paper towel and leave it in a warm area of your house for several days until the root stub shows itself. It’s better to change out the moist paper towel every other day to avoid fungal issues.
Simon