Before I saw the assigned grade, my guess was EF40 also. Agree that the overall light look suggests an old cleaning, but doesn't detract and the coin should make an nice space filler until the "right" coin comes along. Just for comparison here is a really dirty WM from a year later also graded EF40:
Here's the piece that was in my type set for a number of years before slabbing came along. This one flunked at one of the grading services, I forget which one for cleaning. The photo is of a slide, but as you can see, it was a fairly nice coin. I sold it when I was dealer, probably to go into somebody's Dansco Album.
I think the old cleaning was pretty apparent. The only question was, would it straight-grade. My view from the beginning is that it is a beautiful coin, that could go either way. Either the TPG could have gone EF details, or it would straight grade as EF 40. I am very glad that it did straight grade, as it was a judgement call, and could have gone either way. So, it came out the appropriate way. I posted an 1876, with the same issues, and you are welcome to comment on it—the GTG is still active.