Box 12 (Code J) - Generally, the amount of any nontaxable sick pay would be shown in this box. This would be sick pay that was paid by a third-party and was not includible in income (and not shown in boxes 1, 3, and 5) because the employee contributed to the sick pay plan. Do not include nontaxable disability payments made directly by a state. If the payments are subject to income taxes (which they would be if they were paid under NJ Temporary Disability Benefits law) then they would not be entered in this box.
See page 12 - http://www.irs.gov/pub/irs-pdf/iw2w3.pdf
Yes, those entries are correct, assuming the payments are under the NJ Temporary Disability Benefits Law. And as you mentioned box 16 will be different than the other boxes because the payments are exempt from NJ income tax.