Having the most popular subvariety of the Buddha you can't pollinate the flower because there is no stigma, and pistil is spilt into fragments (there's just a little "Buddha's hand" inside the flower). And the citron doesn't form nucellar seeds so... that's why it's impossible to find a seed in the fruit. I've heard pollen is not fertile, but I'm not sure about it. Tried to pollinate a Ponderosa lemon flower with it, and a fruitlet formed but dropped off while being too small to see if there were any seeds.
There's a subvariety called "Muli" or "Xiangyanggo" and it's said to create seeds, because of flowers having a normal pistil and stigma. The seeds should be zygotic, as the citron is monoembryonic.
The albedo is not very tasty when eaten raw, but after mincing the whole fruit and boiling the chaff with mead, you can get a quite aromatic and tasty fluid. A good thing to add to a tea, or when baking.