I am not an expert in these, but I remember this page helped me quite a bit when I was looking through my types. Maybe it will help you as well. You basically need to look mostly at the writings and try to see different letters, they are located on the right mostly lower side of the coins which is opposite from the “octopus man” side.
Got to match the writings, and most of the Raja Raja coins are somewhat degraded in comparison to the Sri Lankan ones. Here is my gold Raja Raja coin to compare as the copper one is similar in writing. While I can tell you exactly which one is which, better to learn to fish…
Ceylon: Raja Raja Chola (ca. 985-1014) AV Kahavanu (MNI-825)
Obv: King seated right, with arm on right raised and holding sankh shell; Devanagari legend on right, below raised arm - श्री रज रज (Sri Raja Raja) Rev: Standing king with ancillary symbols, to left and right
There are sub-types defined as well as clear differences in some coins due to various additional devices. The sub-types are usually due to quality / flan / size differences. That is how Mitchiner defines them, but neither Zeno and certainly Numista has these covered. My catalogs are all in storage at the moment and thus I don't have access to Mitchiner. His Raja Raja Chola coins are all the same and Numista is wrong…
There are sub-types defined as well as clear differences in some coins due to various additional devices. The sub-types are usually due to quality / flan / size differences. That is how Mitchiner defines them, but neither Zeno and certainly Numista has these covered. My catalogs are all in storage at the moment and thus I don't have access to Mitchiner. His Raja Raja Chola coins are all the same and Numista is wrong…