Can a finished FotoMagico v3 slideshow be edited?

I have a version3 FM slide show and I would like to append more current data to it.
The slideshow.app plays perfectly as a stand-alone. In the full FM app the File > Open won’t open the slide show from the Mac Finder, nor will the File > New “Open Existing Slideshow” open the existing but greyed out files.
I’m a newbie to this forum and am just restarting using FM after a hiatus of approximately 5 years, so yes I consider myself a newbie. I have all of the media assets-music and images that I used originally, just not the talent.
Thanks for any clues or directives that you might offer.

Mac Powerbook Pro mid-2012, OS X 10.9.5, FotoMagico v3.8.8

if it is the stand-alone player app, which is sounds as if it is, it cannot be opened by any version of FotoMagico. If you have the original slideshow from which the slideshow.app was exported, it will open and is editable in FotoMagico. I would suggest making a copy of the original slideshow before opening and editing it.

best wishes.

Thanks, I do have the original materials to recreate it if necessary. The problem with being away from using the app for so long now is knowing where it might be archived. Thanks for letting me know about the exported player app. jd