I'd be more worried about the apparent height difference than the width. Width varies alot. Diameter is important.
That's what I would think, too. And from what I've been able to discern after looking at over two dozen tires of that size from various manufacturers like Michelin, Pirelli, Kumho, General, Goodyear, Continental, Yokohama, Toyo, and Dunlop to mention a few, the overall diameter of a new tire of that size seems to center on 25.4". So, measure the new one. If it measures at 25.4" in overall diameter, or within a tenth of an inch of that, then it's right. If not.......
Your old one is probably less since it's worn quite a bit, but should probably within a 1/2" or so of that 25.4" figure.....
Tread width is all over the board, tho. Have seen it "measured" at 9.3" to 10.7" at that size tire.