A pocketwatch, Beastt, a simple pocketwatch. You're telling me that if I held out my hand, blinked a pocketwatch into existence from [literally] nowhere and gave it to you. You still would look for evidence that it was manufactured somewhere?
That's rather beside the point since you're attempting to present an analogy for something which has been the focus of literally ALL scientific scrutiny -- the universe itself. Certainly it has been analyzed, scrutinized, examined, observed, documented and explored.
What if it was an ice cube, instead?
Ice cubes contain things other than water such as trapped air bubbles, (one of the reasons water expands when it freezes). The content of the air bubbles can be examined to see if the contents are consistent with Earth's atmosphere, at what elevation and at what location. If it cannot be matched to any known Earth location, then we have potential evidence that it was not formed naturally on Earth.
Even if it doesn't contain air bubbles, this is a distinct indication that there is something special about this particular ice cube. There are always things which can be examined about anything offered to see if it is consistent with a natural process, a man-made process or a process other than those known. I know this doesn't help your analogy but that is because you've presented the analogy on false pretenses and that's what I'm attempting to point out. You're suggesting that there is no way to know whether something is created via strictly natural means or by supernatural means and I'm demonstrating that the only time this could be true is if the supernatural sentience behind the creation intended to be deceptive.
If you don't believe this then I invite you to keep tossing out examples of something physical which you think would not hold evidence about it's means of "transformation", (since "creation" is an abstract concept never witnessed).
Or a widget? Or a picture of you when you were just 1 year old? Or a book with your entire family tree written down in it, going back 5 generations? Out of nowhere?
Firstly, "nowhere" doesn't exist. No matter where you or anything else is, that is the place where it is. There isn't any "nowhere", except for a small town in Arizona by that name. But even Nowhere, Arizona exists in Arizona.
The "widget" must be defined. You can't hand someone something with indistinct properties. Any photograph will contain clues about it's origin. The film grain, (assuming a film camera since digitals didn't exist when I was one year old), the paper upon which the print exists, the size and shape of the silver halide crystals in the grain. Older films used silver halide crystals of a globular shape. Once it was determined that the shape of the crystals could be manipulated and that T-shaped crystals offered a less "grainy" look, films began utilizing T-shaped silver halide crystals. What shape do you suggest the crystals would be in the photo you suggest? All physical things give us areas to examine to determine the origin.
You're telling me it should show evidence of ex nihilo?
I'm telling you that unless it was produced with the specific intent of making it appear to have been formed via natural methods it would contain evidence of having been produced by methods unlike those known to natural methods. Everything holds evidence regarding its formation. You simply cannot manipulate the physical without leaving evidence of that manipulation. The manipulation itself is evidence of manipulation as well as the marks, contaminents, chemical traces, etc. left upon the physical matter being analyzed.