Are "working dues" on my paystub considered union dues?

Yes.  If they are paid to the union.  Dues paid to professional organizations are deductible if membership helps you carry out the duties of your job. The dues must be common and accepted in your trade and helpful to your business.

If you haven’t yet filed your return, you can include your union dues as an employee expense.  Keep in mind, though, that your union dues will only be deductible IF:

• You itemize your deductions (Schedule A); AND
• All of your unreimbursed employee business expenses and other miscellaneous itemized deductions added together are more than 2% of your AGI.  [Only the amount over 2% AGI is deductible.]

[NOTE:  If you are self-employed, your union dues are deductible on your Schedule C as a business expense and not on Schedule A.]

To include union dues in your return, please follow these steps:

1. Click on Federal Taxes [Personal in TurboTax Self-Employed] > Deductions & Credits.
2. Scroll down to the Employment Expenses section and click on the Start/Revisit box next to Job Expenses for W-2 Income.  [See Screenshot #1, below.]
3. On the Employment Expenses Related to a W-2 screen mark the Yes button and click Continue. [Screenshot #2]
4. On the next screen, Did you have any of these expenses in 2016? mark the Yes button and click Continue.  [Screenshot #3]
5. Continue through the screens until you reach Job-Related Expenses.  Enter the amount of your union dues along with a description.  [Screenshot #4]
6. Click Continue when done