  Recent TeV-scale gamma-ray observations with the CANGAROO II telescope have
led to the claim that the multi-band spectrum of RX J1713.7-3946 cannot be
explained as the composite of a synchrotron and an inverse Compton component
emitted by a population of relativistic electrons. It was argued that the
spectrum of the high-energy emission is a good match to that predicted by pion
decay, thus providing observational evidence that protons are accelerated in
SNR to at least TeV energies. In this Letter we discuss the multi-band spectrum
of RX J1713.7-3946 under the constraint that the GeV-scale emission observed
from the closely associated EGRET source 3EG J1714-3857 is either associated
with the SNR or an upper limit to the gamma-ray emission of the SNR. We find
that the pion-decay model adopted by Enomoto et al. is in conflict with the
existing GeV data. We have examined the possibility of a modified proton
spectrum to explain the data, and find that we cannot do so within any existing
theoretical framework of shock acceleration models.
