4 months post op FUE graft, there is some growth it's minimal in my opinion. Would it be rare to have such little? (photo)

4 months is pretty early to expect a lot of growth. Generally if a patient has no growth at 8-9 months is when they should start feeling concerned, so seeing a small amount at month 4 is perfectly fine.

After
a hair transplant the grafts go through a resting phase during which time you
may lose the graft hairs.This phase can
last several months followed by a growth phase at 4 to 6 months.The newly growing hair is thin at first but will
thicken over time.By 10 to 12 months
you should see the final results.