With the inclusion of Borobudur, I would say their chances have increased significantly, also the designers did mention that they have been looking at fansites for inspiration, and some kind of Indonesian civ has been quite popular. Of course none of this is a guaranty
Forgot to mention, I've actually seen Singhasari thrown around here and there as another Indonesian variation but I didn't include it in the title because people seem to mention Majapahit/Srivijaya much more often
Wikipedia : The national flag of Indonesia, which is known as Sang Saka Merah-Putih ("The Sacred Red-and-White") or Bendera Merah-Putih ("The Red-and-White Flag") or simply Merah-Putih ("The Red-and-White"), or sometimes referred to as Sang Dwiwarna ("The Bicolor") in Indonesian  is based on the banner of the 13th century Majapahit Empire in East Java. The flag itself was introduced and hoisted in public at the Indonesian Independence Day ceremony, on 17 August 1945. The design of the flag has remained the same ever since.
Wikipedia : Javanese traditional batik, especially from Yogyakarta and Surakarta, has notable meanings rooted to the Javanese conceptualization of the universe. Traditional colours include indigo, dark brown, and white, which represent the three major Hindu Gods (Brahmā, Vishnu, and Śiva). This is related to the fact that natural dyes are most commonly available in indigo and brown. Certain patterns can only be worn by nobility; traditionally, wider stripes or wavy lines of greater width indicated higher rank. Consequently, during Javanese ceremonies, one could determine the royal lineage of a person by the cloth he or she was wearing.