The form metrics have not changed in several years AFAIK.
There is actually no 1099 PDF form available for filing because the IRS requires their red ink form stock to be used (you have to print directly on it.)
Here's the 2018 form: https://www.irs.gov/pub/irs-prior/f1099msc--2018.pdf
Here's the 2017 form: https://www.irs.gov/pub/irs-prior/f1099msc--2017.pdf
