So, I am noticing that I have not had to weed out any seedlings from our numerous catalpa trees here yet.
Which must mean they either sprout from very fresh seed, or last year's seed.
In either case, plant them and see. Worst case, you will have wasted a little time, and learn that you need the fresh seed. Best case, they grow and you are a year ahead of where you would be if you had waited.