Yes, but they grow and will fill the 4 inch pot by May. I use glasses at the 225 level
I will start transplanting about mid Feb to 1st of march. I plant out some time between Mothers day and the first of June. Last year was so cold until into June. At this time they should be 8-10 inches tall and become very root bound in those pots. I think that moving seedlings from seed tray to 6pack to four inch is a waste of time and they seen to shock every time you move them. Lost a few when transplanting.
With the big leaves they sun burn easy when first put out. These begonia are more like a cocktail begonia, when harden off, but biger and the blossoms are different. Of couse that is PNW sun. I have never gardened any place other than here so sun for me my be different. I'm sure you know all this but my 2 cents