Yeah if the ribbon is making contact with the pins correctly it should work. As long as you can get a picture on the LCD when you hold it in there you should be fine. Don't use hot glue through.
My advice is to stick it in, put two dabs of hot glue in the corners to hold it in place and verify that it works like that, then cover the entire thing in epoxy. Hot glue is great for some things but if the inside of your case has poor airflow and the glue reach a high enough temperature to soften, the cable could move and lose contact with one of the pads.
Epoxy must reach a higher temp to soften so it's probably the better choice in this scenario.