I don't think you have Hachiya if your trees are truly not grafted as all the named varieties are propagated by grafting. How did you determine that they weren't grafted?
Where did you buy them and did you talk to the seller about them? Seedling Asian persimmons can bear decent fruit, but like other seed grown fuit trees will be unpredictable.

I bought them from a local nursery. The person I spoke with really didn't know anything about them. The info label identified them as kaki, but didn't name the variety. However, two things led me to believe that it's Hachiya. This nursery only sells the most common commercial fruit trees. And, the photo on the info label, if correct, looks exactly like a Hachiya persimmon. Of course, I won't know for sure until it fruits.

I checked both trees thoroughly for signs of grafting, and there isn't any that I could find. When I bought the trees, they were already 6+ feet and multi-branched.

I was just curious that if they truly aren't grafted, what effect it would have on growing habits and fruiting. Sounds like it could still fruit true.

On a 6' tree it can be hard to find the graft, so my bet would be it is there but has gotten too hard to see. If it is a seedling it will take longer to fruit and the fruit will likely be inferior.

Scott

I know it's hard to believe, but Persimmons can possibly be propagated from cutting, although it's difficult.
As far as the ungrafted tree, it's true it might be very hard to find the graft on a large tree. I know of a couple nurseries that sell American persimmon trees that are seedlings.

Bass

Very unlikely that these are seedling kakis as there really is no market for them and they are relatively difficult to grow. You would have a great deal of trouble finding them even if they are what you sought. As Scott mentioned they may be grafted kakis with grafting evidence too subtle to be easily perceived, or they may be rootstocks of lotus or American persimmon that out-competed a previously made kaki graft that subsequently died off. You will be able to distinguish between these possibilities once the trees leaf out in the spring.