The sign which Raoul posted to send the Spanish troops in the wrong direction contained several errors, which would cause those troops to be suspicious of the sign. It reads "Pelligro - Minas Fascistas - Deviacion por Blanes¡" It should read "Peligro - Minas Fascistas - ¡Desviarse por Blanes!"
Savory is watching the communist convoy. It's led by an armoured car, a British Daimler Dingo to be exact. The problem is these vehicles first went into production for the British army in 1940 while the Spanish Civil War ended in 1939.