Digital BW, The Print

Like Tyler says there is no way to know how it will output with a
particular printer driver combination. I well set up system should be
close to what you view on a good monitor in greyscale mode. Mostly
what you will probably run into will be slight density differences but
you could end up with slight contrast variations as well. As we all
know slight difference in black and white output can transate into big
differences in visual impact.

If it were me I would convert the file to Grey Gamma 2.2. View it on a
good monitor for midtone brightness. Then check the numbers in
Photoshop for your extremes with the eye dropper tool set at 3x3
average - make sure good shadow info within  important areas doesn't
drop below about 95 greyscale value in PS ( Remember 100 is pure black
and 98 and 99 is still usually visible as something other than total
black with a good inkset) and the brightest highlight values are not
blown out at 0. I will almost put any large area of tonality at at
least 1 or 2. At that point all you can do is have them do a test. 

As any good black and white printer will tell you there is so much
that is subjective, even with a perfect file. Curves is where the
creativity lies. That is why I always do proofs of everything if I can
for a client before outputting final things. I would ask for that.
Even a 5x7 proof of your file can tell you a lot. If you are in
another town and are spending money on this Fed Ex the proofs first.

John