  We show how to match the Isgur-Karl model to the spin-flavor quark operator
expansion used in the 1/Nc studies of the non-strange negative parity L=1
excited baryons. Using the transformation properties of states and interactions
under the permutation group S_3 we are able to express the operator
coefficients as overlap integrals, without making any assumption on the spatial
dependence of the quark wave functions. The general mass operator leads to
parameter free mass relations and constraints on the mixing angles that are
valid beyond the usual harmonic oscillator approximation. The Isgur-Karl model
with harmonic oscillator wave functions provides a simple counterexample that
demonstrates explicitly that the alternative operator basis for the 1/Nc
expansion for excited baryons recently proposed by Matagne and Stancu is
incomplete.
