It is mentioned nowhere in accelerate framework that it uses atlas, and they removed functions like ATL_buildinfo. I doubt it has changed much in the last 5 years as well, and I am not sure what makes you think there is ( significant) non-atlas code in there ? Besides symbols starting with ATL, I see mostly the BLAS/LAPACK API, although I did not try to check very carefully.
Besides the ATL-prefixed symbols, there are are numerous APL-prefixed symbols, as well as many _block_ symbols which indicate extensive use of GCD in the level 3 routines (and which ATLAS doesn't use).
