Doug, I am growing a couple Hunza apricots from the ARS collection --
they have several that Thompson collected there years ago. They are
not very precocious but I hope I can get some fruit this year (I think
they were grafted about five years ago).
What I wanted to add was they are not late blooming at all, they boom
with my other apricots. The only ones I have found that are later are
the white varieties; this year Zard, Canadian White Blenheim, and
Shekar Pareh were about a week later than the rest which were more or
less synchronized.
Note that when any foreign seed of a stone fruit is grown out there is
a risk for plum pox.