Looks to me, like if they are plain text, you should be able to search and replace to remove the et al and punctuation leaving {Author, YEAR #recno}, but the record numbers won’t match so you might need to go thru it once to associate the correct reference. If you could import whatever bookends is using as the record identifier number into the label field, you could get rid of the # in a search and replace and tell endnote to look for the label field as the unique identifier. (you change this setting in Endnote in Edit>preferences, “temporary citations” settings. To get to the instructions, you need to search the knowledge base here for bookends. But I copied the instructions below.
The good thing, is that Endnote allows you have a free trial, so you could test it before purchasing? Maybe try it on a chapter.
conversion:
EndNote : Importing references created in Bookends into EndNote
You can import a Bookend library including Notes and attachments into EndNote. Using Bookends 8 and later you can export data into EndNote XML format files that can be imported into an EndNote library using XML as the import option.
Please make sure to select the Import Option as “EndNote Generated XML" while importing the XML files. This should import the references properly in to EndNote.
The comments that are entered in Notes field in Bookends will get imported into the Notes field in EndNote. And any attachments in Bookends will be linked to the attachment section in EndNote.
However, the link for these attachments will remain to be the attachments folder of Bookends(which is absolute path for EndNote). Hence, if you are planning to move your EndNote library after creating one from Bookends, the attachments may not work on the other computer as the attachments are available only on this computer.
You will need to change the absolute paths to relative paths which will make sure that the attachments are moved into EndNote’s PDF folder(.data folder). In order to achieve this, once the importing is done, select all the references which are imported -> right click and select File Attachments and click on Convert to Relative Links.
You can now move this EndNote library to other computer with attachments using the compressed library feature.