Employer HSA Contributions Not on W2

Hello,

 

I have an HSA where $400 were contributed fully through my employer and not deducted from my paycheck. These were the only contributions made to my HSA this year. From my understanding the $400 should be included on my W2 box 12 with code W even though they weren't through payroll deductions, correct?

 

Additionally if that is the case, should the $400 be included in box 1, 3, or 5. Are the $400 contributed by my employer that are not taken out of my paycheck included in my taxable income, and medicare and social security wages?

 

For example, should the boxes 1, 3, or 5 be $400 higher if the contributions were reported correctly?

 

Just trying to have as much information as I can regarding box 12 code W not being on my W2 and the impacts it has on the other boxes as well. 

 

Thank you!