I suspect - but I don't know for certain - that your wife's 1099-R from the NJ Pension Plan already takes her post-tax contributions into account, and that the amounts in Boxes 1 and 2a are correct.
You could contact the NJ Division of Taxation at (609) 292-6400 to see if this is correct.
https://www.nj.gov/treasury/pensions/documents/factsheets/fact12.pdf
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
