Almost 100% of the time you will see accelerated growth of lepomids in a brand new pond.

I'd almost bet my last dollar that those aren't the original stockers.

Just my opinion, and I can't say when those were spawned, but I have YOY redears that are 1-1.25 inches right now, and I'm as far north as you, right? If that happened in my pond, I would think that your bigger, newer pond has a great chance to have 2008 class fish that are over an inch. It is almost August, after all. ;\) I'll bet you have an unbelievable invertebrate profile. Very few bigger sunfish to crop off the bigger adult invertebrates.

...and those are definitely redears.

Holding a redear sunfish is like running with scissors.