This response is based on the information provided.  We suggest you discuss with your contracting team, program manager and/or legal department as appropriate. 

The FAR addresses taxes in two spots that relate to your question.  In general, state taxes are an allowable cost.  We point you to FAR 29.303:

"(b) When purchases are not made by the Government itself, but by a prime contractor or by a subcontractor under a prime contract, the right to an exemption of the transaction from a sales or use tax may not rest on the Government’s immunity from direct taxation by States and localities. It may rest instead on provisions of the particular State or local law involved, or, in some cases, the transaction may not in fact be expressly exempt from the tax. The Government’s interest shall be protected by using the procedures in 29.101."

Additionally, at FAR 31.205-41, the FAR states:

"(a) The following types of costs are allowable:

           (1) Federal, State, and local taxes (see part  29), except as otherwise provided in paragraph (b) of this section that are required to be and are paid or accrued in accordance with generally accepted accounting principles. Fines and penalties are not considered taxes."

Of course, read surrounding material at these citations to get full context. 

We found nothing additional in the DFARS, DFARS PGI, AFFARS, or Class Deviations although we do not have access to much of the USAF linked material.