Thank you for your post.
There is nothing built in FileMaker Go that would not allow the same guest access to a file as FileMaker Pro, unless there is a Startup script that checks for the Application name or platform when opening the file. Do you have a Startup script? If so, what are the script steps being executed? Specifically, anything that may stop access because of the platform? If not, then I would like to see your database file so I can try it here. Check your Inbox at the top of this page for instructions where to send the file.