When Holden is putting the cross together inside the task force headquarters he uses a cordless drill to secure the screws. There were no cordless tools available at that time.
(At around 51:50) While Holden is running toward the church, a CNN van is seen in the background. The logo is their modern red logo, but from 1980-1984 their logo was black.
Battery-powered electric screwdrivers are used to assemble the crosses, but they were not in wide use in the time period, primarily because they lacked power.
No one in Atlanta has the money to buy four pieces of lumber nor the skill set to nail them into two crosses.
There is a female Lutheran chaplain, but they keep referring to the Lutheran pastor as 'Father Monahan', which is Catholic terminology.