Firefox backup issue:

This is concerning restoring my Bookmarks after having to replace my laptop PC. For the past several years I’ve been backing up my laptop to an external hard drive. I’ve always included the User subdirectory in that backup. The User/Dave/Appdata/Local/Mozilla/Firefox/Profile s/d is included. Today I needed to restore bookmarks from a prior backup in April, 2012 after reading the Firefox help on this subject, I accessed my external drive and looked in the s/d mentioned above. However when I clicked on the “wp83jzms.default” file, instead of seeing a list of backup dates from which to choose, I only saw files with “Cache” and “unclassifier” in the file name. Where are the backed up bookmarks from that date? I also noticed that a different backup had stopped capturing files part way into the Local s/d so that the Mozilla s/d was not written to backup. Wonder what’s up there? I’m using Windows 7 and Firefox 13.0.1