there is really know way of knowing for sure unless we have the sire and dam of a horse, or at least their registered name.
you are welcome to go to my site http://www.davenporthorses.com and see photos of other Davenport horses. Feel free to follow all the links from my sites, the vast majority lead to other davenport owners as well as info about the Davenports.
This bloodline has purposely been kept very diverse in looks and with as much in pedigree as was and is possible, so there really isn't one distinctive look for us to be able to look at a horse and say YES THEY ARE!
We have Davenports that hit an honest 15hh + and we have horses that are lucky to hit 14hh.