I have to check again, but when the target was first proposed (a while back), I measured the target and the rings were very close if not the same.
But another issue is in the printing. If you are printing a JPG or PDF image, if you let the computer scale to "fit the page" you will be getting scaling adjustments. On the PDF you need to print w/o letting it adjust to fit the page. On the JPG more difficult, but same issue.
But here is an idea, for the person that produced the JPG of the targets. Would you make another target, but include a measured line. The longer the better, example 5 inches. When you print the target, you measure the line, if you do not match the indicated length then you know your target did not print the proper size.
OR measure the diameter of the black 7 ring, and use that as a reference.
On the ISSF/Olympic/NRA 10m AP target, the 7 ring is 59.5mm in diameter, and the 1 ring is 155.5mm in diameter.
One thing to be aware of, some computers/printers do not print the same in vertical and horizontal axis. You may get a circle 60mm in diameter on the horizontal axis and 63mm in diameter on the vertical axis. So you have to measure both axis. Some printers are worse than others. Same thing happens if you photo copy your targets.