Basically I came across this citation in the wiki of arthashastra
https://en.m.wikipedia.org/wiki/Arthashastra#Authorship,_date_of_writing,_and_structure
Scholars such as R. P. Kangle theorize that the text was authored by the Maurya prime minister Chanakya.[39] Others, such as Olivelle and Thomas Trautmann, argue that this verse is a later addition, and that the identification of Chanakya and Kautilya is a relatively later development that occurred during the Gupta period. Trautmann points out that none of the earlier sources that refer to Chanakya mention his authorship of the Arthashastra.[39] Olivelle proposes that in an attempt to present the Guptas as the legitimate successors of the Mauryas, the author of political treatise followed by the Guptas was identified with the Maurya prime minister.[40]
I hope I would learn about any counter claims or supporting claims to the above or any elaborate explanation to the above
So I've written a book about Chanakya (Chanakya: Artha). I've had to read almost the entirety of the version by L.N Rangarajan. So I've read a secondary version.
There could've been additions to the Arthashastra. But I do think parts of the book if not all of it were written around 300B.C. The reason I say that is due to the section on warfare. It emphasises the use of war chariots. Chariots went out of fashion after the rise of the Shunga empire as there aren't any sources that indicate the use of chariots. So the Arthashastra couldn't have been written any time later than 180BC.
One thing you do realise reading the Arthashastra is that there are additions to earlier schools of thought. Many of these schools we have lost, however there could be arguments made that more was added to the Arthashastra as the years went on, it is entirely feasible. But given one of the major parts of his Magnum Opus is clearly dated to 300B.C. It is hard to imagine there was much addition or much was abridged.