Yes, it will show an enhanced Product Listing-style table with specification columns. Check that your category has the Display the products in this category: selection set to Detailed table mode (include Specification columns). That will only work if there are specifications associated with that category and they have the Show Comparison selector set to True.
I did write a "select to compare" module for this, but it's only in the Beta version I posted a few pages back. That version requires a lot of advanced features, such as Modular Categories, that are only now being incorporated into osCommerce. You're welcome to use that code, but you will need to do some hacking to make it work with stock osCommerce.