All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
This is nothing beneficial pertaining to this life or the Hereafter based on this question, and it is better for the Muslim to concern himself with useful matters and to overlook insignificant things.
Neither the Quran nor the Sunnah discuss the location of these tablets.
There are, however, some Hadeeths narrated about the tablets. In a Hadeeth on the authority of Ibn ‘Abbaas the Prophet , mentioned that when Allaah The Almighty told Moosaa that his people had worshiped the calf, he did not throw down the tablets until he saw them with his own eyes. Moosa was so enraged by his people's conduct that he threw the tablets down and caused them to break. [Ahmad, At-Tabaraani: Al-'Awsat & Al-Kabeer, Al-Haakim] Ibn Hibbaan and As-Suyooti classified it as Saheeh (authentic).
Ibn ‘Abbaas also mentioned that Moosa was given six tablets, but after he threw them down, two were lifted (to Heaven) and four remained. [Abu Daawood]
For further information on this topic, please look at the books of Tafseer (Quranic exegesis) on Chapter Al-'A‘raaf, verses no.145 and 150.
Allaah Knows best.