Generally speaking ammonia is an inadequate nucleophile for aminations, the yield would be low, and it gives rise to byproducts in form of secondary- and tertiary amines. It CAN be used but is often avoided.
From Advanced Organic Chemistry, 4th ed. p. 899, on reductive amination: "When the reagent is ammonia, it is possible for the initial product to react again and for this product to react again, so that secondary and tertiary amines are usually obtained as side products."
Of course you can prevent it by using a large excess of ammonia, but there would still be the problem of ammonias lousy properties as a nucleophile.
I would employ the Leuckart reaction if I was going for PPA from L-PAC, but that's just me.