I can confirm with many projects I have duplicated page code therefore not having particular sessions assessble in the bindings panel doesn't affect the running of the website... Simply put you could just copy the code into Notepad and save it as a PHP file and running on a local host or upload it to a love host and it will work :) Dreamweaver is just a WYSIWYG editor to help development...the only reason you see the sessions in the bindings is that they are stored in little _notes folder in the root of the website they are .MNO folders...open them in notepad and you will see the sessions defined ....you could backup these files and then copy them to a new project ;)
Chris