In the ingots I've turned into bars (and the bars I've used before) it's similar throughout. Although logically, the middle of the bar would be a bit more streached out because it's more material drawn out but it's not that noticeable and perhaps the pattern is slightly more pronounced on the outside of the ingot. There's no significant difference I could see.
That said, it depends on the smelter and the process used. I've seen plenty of bars at knifeshows that had crunchy bits in them from material that hadn't mixed properly. And I've been told that sometimes if the smelting didn't go right, you might get a low carbon 'dead spot' or a cold shut. I did find a cold shut once, during grinding.
I was told by Niko to first flatten the ingot to a pancake, and then draw it out again. He told me this creates a lot more distortion and lengthening, compared to going straight to a bar shape. That makes sense imo. I recently saw someone punch a hole through an ingot, cut it, and then pry it open like you would straighten a piece of coil spring. You'd get the same length of drawn bar, but the pattern would hardly be stretched at all because you fold the ingot open instead of drawing it.
A local who is trying to bloom wrought iron from local magnetite has contacted our local smithing group for advice. I'm planning on going to see his set up and possibly help him with some tooling in a couple of weeks. Anyone know anything about a bloomery for wrought iron? He has tried a few times and come close, but he thinks he should get better blooms.