Can you limit documents to just "preview" and not "download"?

I'm looking at using this as a document manager for our intranet using the Woffice theme. We are a credit union, and want folks to just open the files without downloading them. It seems as if the "preview" button would give us that flexibility. Is there a way to remove the download button and just have the preview one? And is it possible to rename that to something else, like "open"?

This gives the employees the ability to upload documents correct? That way they can manage them. Update when necessary, etc or even delete them.

And the search engine will index the content of all pdf's, not just the file name correct?

Thanks!

Russ