Dimitris,
Do all pages of the same manual get the same revision number and date, or is this a per-page revision ?
If all pages get the same number and date, you can use FrameMaker variables and do not need a script at all. Just enter the frame on the master pages as non-user-editable text and enter a user variable into it. Changing the user variable gives you the required result.
If each page requires its own revision number and date, scripting will not help you. How are you going to get the revision number and date per page? But even if sections require their own revision number and date, you can divide the entire document into chapters in a book (continued page numbering) and do the same with the FrameMaker variables.
So I do not see a need for any scripting. If you do need this done via scripting, I think you should ask someone like Rick or myself to do it for you for a reasonable fee. What you think is easy is in fact not so straightforward.
Kind regards
Jang