These manufacturers however did not immediately take the "Modèle 37" into production; they in fact made the "Modèle 31" to complete the first production batches; only in the summer of 1939, when the French economy went into full gear to prepare for increased war production, was the gradual transition to the UE 2 really made, though some new features, such as the mudguards, appear already in the summer of 1936; from the summer of 1937 instead of the original "Restor" headlights the armoured type of "Guicherd" was fitted. The Army did not discern between the two UE types and eventually in the statistics subsumed all "chenillettes" received under the denominator "Modèle 31". On 1 September 1939 2848 Renault UEs of both models had been manufactured. In 1940 a production of 300 vehicles per month was aimed at. To ensure such a high output Renault bought the SUP factory at Pontlieue, to start another UE 2 assembly line there. On 1 April 1940 AMX had built 1080 Renault UE2s, Fouga 260 and Berliet 310. In May monthly deliveries reached the total number of 509, made possible by emptying the factory matériel stocks; on 1 June 4977 Renault "chenillettes" of both models had been built, 4557 delivered; total production destined for France was about 5148, on the assumption that about 2300 vehicles had been produced after 1 September. In the seventies it was still assumed that the production realised before December 1937 — mistakenly equated to that of the "Modèle 31" — was not included in this number; total production was thus overestimated at about 6200.