That's definitely an aftermarket wind, as others have stated, but I question whether it really is wound like a true 125A1A. According to Bryan Sours on the Soursound website, the 125A1A is, "A deceptively difficult transformer to wind thanks to it’s layer density and 5 section interleaving (all layer wound of course) ..."
I wonder if an inexpensive replacement OT is wound as quickly as possible on modern equipment to just achieve the correct impedances and winding ratios, or, do these companies go out of their way to truly provide 5 sections of layer wound interleaving at that price? The sound of the original has a lot to do with the quality of metals used and the type of wind in addition to the impedances and ratios.
Soursound's 125A1A sounds nothing like any of the others; it's quite the departure. It's what got me thinking about this lately. I'm not trying to push a brand into the conversation, just questioning if typically a replacement OT is actually a true reproduction of what it's claiming to be.