NO, but it depends on how thorough you want to be. first I'd clean off the fork tubes and ride it for a week..any oil sludge appearing on the tubes ='s you need new seals.
Draining the fork oil w/o a rebuild means you'll get 90% of the oil out. If you flush the tubes with a solvent you can get more of the sludge out but then have to flush with clean oil at least once to remove solvent. I assume your bike is down for the winter..good time to rebuild forks???
Drain is presented above (quite well indeed) - you'll find a soft-coper washer under that drain bolt to act as a seal.
On your '88, you'll end-up pulling the fork caps anyway to get to a point where you can refill the tubes (unless you wanna figure some way to pressurize your replacement oil up through the drain hole).
You won't need to pull the fork or tubes, just be sure that you've got the forks fully extended and have a good plan to catch and reinstall the fork-cap against the spring pressure. (pulling the fork caps will require a 17mm allen, after you've loosened the top tube clamps on the triple-tree).
If ya wanna, you can flush the forks with DextronIII ATF, which offers an excellent detergent package with good dispersants (also the 'fork fluid' specified for the early bikes)