Neither Mulder, Scully nor Skinner declare themselves as Federal Agents while chasing the suspect Ed Truelove. He could have protested that the arrest was unlawful.
Reflection of the camera is visible (upper left side) in the mirror of the interrogation room at 22:05 before Mulder enters with a video tape.
Interstate 74 does not go all the way West to California; it ends at a junction with Interstate 80 in Davenport, Iowa. It also does not run North-South, as the sign indicates. It runs East-West, as all even-numbered highways do. Odd-numbered highways run North-South.