Yes. There are references of Ramachandra in Valmiki Ramayana. But Rama is not directly called Ramachandra. Sage Valmiki compares Rama with the moon i.e., chandra while describing his life at Ayodhya. The name "Chandra" is added to the name Rama by the citizens of Ayodhya city. They felt like flowers which wait for the rise of moon when Rama was away from them. They felt happy if they just look at Rama. There were only two types of people who were unhappy in Ayodhya.
Who didn't see Rama.
Who were not not seen by Rama.
They were very affectionate towards Rama that they did not care for their food and activity if they have seen Rama's coronation. It is described in the Ayodhya Kanda sarga 17 of Valmiki Ramayana.
अलमद्य हि भुक्तेन परम अर्थैः अलम् च नः || २-१७-१०
यथा पश्याम निर्यान्तम् रामम् राज्ये प्रतिष्ठितम् |
"If we can see Rama going forth in the city after getting coronated today, it is enough of eating or other activities."
ततः हि न प्रियतरम् न अन्यत् किंचित् भविष्यति || २-१७-११
यथा अभिषेको रामस्य राज्येन अमित तेजसः |
"There is no other dearer thing to us than coronation of Rama of unbounded splendour".
न हि तस्मान् मनः कश्चिच् चक्षुषी वा नर उत्तमात् || २-१७-१३
नरः शक्नोति अपाक्रष्टुम् अतिक्रान्ते अपि राघवे |
Though Rama became distant, no one could turn back one's eyes and mind from him, the best of men.
यश्च रामं न पश्येत्तु यं च रामो न पश्यति || २-१७-१४
निन्दतः सर्वलोकेषु स्वात्माप्येनम् विगर्हते |
All the people blamed the one who did not see Rama and the one who was not seen by Rama. Such a person would blame himself of it.
They were disappointed very much when they didn't have a look at Rama and waited for him just like we wait for the beauty of the full moon when there is a new moon.
They waited for Rama's arrival when he went away form them and went to his father just like the ocean waits for the moon to rise.
तस्मिन् प्रविष्टे पितुर् अन्तिकम् तदा |
जनः स सर्वो मुदितः न्ऱ्प आत्मजे |
प्रतीक्षते तस्य पुनः स्म निर्गमम् |
यथा उदयम् चन्द्रमसः सरित् पतिः || २-१७-२२
When Rama went nearer to his father, all the people there were delighted waiting for his return as the ocean waits for raising of the moon**.
As Rama is compared with the moon in the above shlokas, the name Ramachandra became popular. This was widely used by his devotees, poets etc.,