As long as the gallery's structure has not been changed with a galleryURL or a baseURL (ie. all the gallery files are in the same folder), you can download the gallery from your web site (via FTP) to your computer's hard drive and then open it directly in svBuilder-Pro to edit it.
Otherwise, you could simply copy and paste the configuration options from your gallery's XML file (the attributes to the opening <simpleviewergallery> tag) into the XML file of any other gallery to replicate its layout.