  While kilohertz quasi-periodic oscillations (kHz QPOs) have been well studied
for decades since their initial discovery, the cause of these signals remains
unknown, as no model has been able to accurately predict all of their spectral
and timing properties. Separately, X-ray reverberation lags have been detected
in AGN and stellar-mass black hole binaries, and reverberation may be expected
to occur in neutron star systems as well, producing lags of the same amplitude
as the lags measured of the kHz QPOs. Furthermore, the detection of a
relativistically reflected Fe K line in the time-averaged spectra of many
neutron star systems provides an additional motivation for testing
reverberation. While it has been shown that the lag-energy properties of the
lower kHz QPOs are unlikely to be produced by X-ray reverberation, the upper
kHz QPOs have not yet been explored. We therefore model the upper kHz QPO
lag-energy spectra using relativistic ray-tracing functions and apply them to
archival RXTE data on 4U 1728-34 where upper kHz QPOs have been detected. By
modeling the time-averaged spectra in which upper kHz QPOs had been
significantly detected, we determine the reflected flux fraction across all
energies and produce a model for the lag-energy spectra from X-ray
reverberation. We explore the dependence of the modeled lag properties on
several different types of reflection models, but are unable to successfully
reproduce the measured lags of 4U 1728-34. We conclude that reverberation alone
does not explain the measured time lags detected in upper kHz QPOs.
