  Possibly the only unambiguous verification that gamma-ray bursts (GRBs) are
at cosmological distances would be the observation of multiple images of a
gravitationally lensed burst. Each images would arrive at a different time, but
exhibit identical light curves. We improve upon previous calculations of GRB
lensing by using revised cosmological burst models based upon better knowledge
of burst spectra, and we consider several sets of cosmological parameters. Only
lensing by the known population of galaxies is considered, and we compute the
lensing rate and amplification bias using three different lens models. Assuming
that 800 bursts per year are above the detection threshold of the BATSE
experiment on the Compton Gamma-Ray Observatory, we predict one lensing event
every 1.5--25 years, with a median time delay between images of about 7 days.
However, BATSE has an instrumental efficiency of about 12\% for detecting
double bursts, decreasing the detection rate to fewer than one per century for
some cosmological parameters. This inefficiency can be overcome partially if
cases of quadruple imaging by elliptical potentials are common, but simulations
show that lensing by elliptical potentials enhances the detection rate by only
about 20\%. We conclude that it is unlikely that the BATSE experiment will
detect a lensed burst, but that a future experiment, which is either much more
sensitive or has a much more efficient duty cycle, could.
