Looks elmy to me but photos aren’t that clear on my device, and guesses are always limited to oak, elm, beech, sycamore, ash, and mahoganyish as that’s all the timbers I’ve ever used.
My vote is for Elm. My parents have a 400 year old farm house and the first floor has Elm floor boards, they are exactly that colour (or darker) and marking.
I'm pretty sure it's not elm, although that was my initial thought. The secondary wood such as the saw till sides and backs look like mahogany, but all of the surfaces and the till bottoms are the mystery wood. I suppose I'll have to go microscopic and take a look at the end grain of the tiny dovetail pins with a loupe to get a definitive answer.
Once it's all cleaned up, I'll show some photos of the precise cabinetry and how he has set the screws right at the edge of the boards and even cut down the width of the hinges to accommodate the thin till sections and lids.