The most perfect one so far is the WE 1911 but it requires a modification, a small line on the top the slide.
Its unmarked, a nice metal. and pretty much is identical
I went to a real gunshop that makes repairs to have that thing build and some how attached to the gun. They even made fun of me for coming with a toy there. But hey, as long as I pay.
Other ways to do it is finding some one that would 3D print it in metal.
Final and maybe more accurate way is to email WE in just making the slide the way you want to. If the Silverballer Mark 1 tend to be quite close in details. I will do this for sure regarding the cost.
But in either 3D print it or custom from factory, its going to cost some where under the 1k €