95 Regal Gas Cap

Hey guys, last year I was gifted a 95 Regal with 152,000km and she runs like a charm. I just posted in regards to my hood not opening at the moment, but I just figured I'd make another post regarding something else. The gas cap door is not attatched. That's how I got it. I mean, the twisty key locked cap is still in tack, so I figured it's not a big deal.. just esthetics, right? 1st off, am I right in not really paying it much thought as the locked cap is still there? or can it be a bigger issue. Also I have the actual door to the gas tank sitting in my trunck but have NO IDEA how to install it properly...

again, any help?

thanks,
dan