What script do you think the Luchos were written in?
Machlokes if written in Ksav Ashuri (like our sifrie torah) or
Ksav Ivri.
Ksav Ivri was used for most writing in the time of Bayis Rishon. Sifrie Torah may also have been written in Ksav Ivri at that time. See the script on a modern Israeli Shekel coin.