The valve gasket will likely leak, or at least seep a little oil.
Go on and change it.

Terry

kit on ebay?  honda oem?  personally, given that the price difference is
not very large between oem and aftermarket, i'd only use oem parts from
a honda dealer because the quality [and life] is so much better.
manchester honda do belt kits.

yes, it's worth doing the water pump.  those seals go, and when they do,
they ruin the bearing causing it to lock solid.  you don't want that on
the timing belt!  oil seals, and tensioner may be ok.  inspect closely.
 play in the tensioner pulley [surprisingly, for me] is normal - i
swapped mine last change because i thought pay in the bearing meant it
was shot, but the new oem tensioner was exactly the same.

if you do the job yourself, and you pay close attention to the conditon
of your car, i say it's ok to proceed as above.  if you're reliant on a
garage, have them change the lot because not everyone knows what they're
doing and they may miss important stuff.  i got my crx cheap because of
a suspected broken belt.  it was actually the water pump siezed.  the
belt had been changed twice according to records, but the pump never
changed. [!]  the previous owner had been losing coolant and had had a
new head gasket, new radiator, thermostat, hoses, everything except the
pump.  cost a fortune & they never correctly diagnosed the problem.
preemptive replacement rules this kind of problem out.