Matchbox #1 Mercedes Truck and #2 Mercedes Trailer

This is from the 1-75 series. When a new model was introduced an older model was removed from the line. The Mercedes Truck is known as the 1E being the 5th model to have the #1 designation. I believe the other four were steam rollers. The Trailer is the 2D, the fourth #2 replacing the Muir Hill Dumper. Previously new models were improved versions of the previous model but this was dropped in the late 60s.
Both of these models were introduced in 1968 and feature a removable canopy. The truck has an F style box which means it came from the first half of 1969. The trailer is in an E style box which means it is from 1968.