It is not illegal to carry into a Work One office. It is against policy. 35-47-11.1 only applies to local restrictions. Because the Dept. of Workforce Development is a state agency, they're not covered by 11.1. They can, and will, ask you to leave if found. The guards are not police, they are hired security and have no arrest or law enforcement powers. They are there to provide someone to shoot back if someone starts shooting first. They are only covered by the IC for self defense/defense of others just like ordinary citizens.
I contacted my State Senator regarding the sign @ a location in Indy & was told that they could post & prohibit since they were a sort-of-combo state-private company..