Every time you complete your personal conquest, you receive a lockbox with three random conquest Crafting Node Decorations, one of which could possibly be a Galactic Archaeological Find. You get a second lockbox if you complete your guild conquest goal as well.
If you're looking to get a Galactic Archaeological Find and haven't gotten lucky with your conquest rewards, you can buy one from the GTN from another player. These decorations are farily inexpensive because there is an unlimited supply - more are created every time someone finishes their conquest goal.
Leave a comment, question or screenshot about the Galactic Archaeological Find deco in the Disqus comment box below!