In short: go for it. I doubt there's little to lose, but much to gain.
The pros:
**Good karma*
never a bad thing to have.
**More attention to our website*
possibly a con if your code is really bad :)
**Perhaps getting fixes and improvements from others*
this is possibly the best thing you get from open-sourcing your code. Its all about sharing and helping each other, you get to use other's code, they get to use yours and everyone's gained from the trade.
The cons:
**Without investing more development, the tools might make us look bad*
I'd search through to remove dodgy/rude/stupid comments, tidy up the formatting etc.
**Publishing of the code requires some effort*
requires barely any effort - set up an account in Sourceforge, create a SVN repo there and import your code. Then create a binary package (a zip file will do) and release it using the website. Might take you an hour, if you stop to read all the documentation.
**Some of the tools might be too specialized for our needs*
You could set the whole lot up as a group - eg PowerBuilder Tools, then people who see the really specialised tools won't have wasted their time getting them, they'll still have the 'more readily useful' tools.
**The whole effort might go unnoticed given the shrinking community*
Possibly, but then there's really no reason not to release the code. If you don't it may get completely lost to everyone when/if you change development tools.