Potential stolen design.

Is there a way to tell when someone posted a file? I designed a computer arm digital file for cnc use about a year ago when I started my shop. Last year I sold a couple of dozen downloads. I was curious so I did a search to see how far up my listing was. I. Doing this I noticed right next to my post was someone else selling a file that looks almost exactly like mine. While this could be coincidence there are some uncanny resemblance. I’ll attach some photos, mine is the first one (I have updated the picture to show the physical item instead of a rendering). Is there a way to see when someone posted there items for sale? I’m sure there is no way to prove anything, it’s just frustrating seeing something that looks exactly like my hard work and time designing and developing being sold less than mine right next to mine in a search.