To draw a real conclusion I would have to find four sets of seedlings, three each, pot two of each set, put one in the sun, leave one in the shade beside the one in the ground, and look for consistent differences.
That is way too much work.
Actually, there were several still in the ground, and they were sort of consistently the same size, as were the ones in pots. Some pots are noticeably smaller and those trees were a little smaller.
Conclude what you like, I'll leave the trees in the sun.