Eugenia Pitanga can produce ribbed fruits. Therefore, they are less perceptible.
About the seedlings, the leafs are from a normal pitanga, as the fruits in the first photo.
Anyway, Eugenia Uniflora is to much variable, and sometimes can produce fruits before two years. But not when in 30 cm tall. Just Eugenia pitanga can do this.
The problem with Uniflora is the flavor. Not all the trees produces fruits with good flavor. Just an advise: don´t buy the tree without to taste de fruits.