Could be quite possible, but I suggest you read the report on this link. Even this "theist" was skeptic about this finding.
http://s8int.com/dinolit25.html
This analysis revealed three important facts: a) The engraved stones have a higher specific gravity than common river rocks found in riverbeds and beaches, which I had guessed as soon as I first held one in my hand;
b) The engravings are old, to judge by the coating of natural oxidation that covers the incisions as well as the stones themselves; and
c) The stones were engraved not long before being deposited in the spots where they were found, to judge by the absence of wear on the edges of the incisions, which means that the stones were not engraved for utilitarian or even artistic purposes, but rather to be deposited in a safe place - for some unknown reason.
One year before, Santiago Agurto Calvo had published the results of a petrological analysis of the engraved stones in his collection. These results were part of the newspaper article mentioned earlier, in which he discussed the discovery of engraved stones in the Ocucaje zone.
Specifically, the article dealt with some specimens that he had purchased in 1962 from huaqueros which, according to him, contained "unidentifiable things, insects, fish, birds, cats, fabulous creatures and human beings, sometimes apart and other times shown together in elaborate and fantastic compositions".
He had entrusted the analysis to the mining Faculty of the Universidad Nacional de Ingeneira and it had been performed by two engineers, Fernando de las Casas and Cesar Sotillo.
Since the analysis I had commissioned promised that the preliminary study would be followed up by a closer examination in the laboratories of the Universidad Nacional de Ingeneira de Peru and the University of Bonn, I decided to compare the analysis of my stones with that of the stones of Agurto. The analysis of Agurto's stones read:
All the stones are highly carbonized andesites, despite their coloration and texture, which suggest a different nature.
The stones come from lava flows dating from the Mesozoic era, characteristic of the zone where they were found. The surface has weathered, and feldspar has been turned into clay, weakening the surface and forming a kind of shell around the interior of the stones.
This shell measures an average of grade 3 on the Mohs scale (which measures the comparative capacity of a substance to scratch another or be scratched by another) and up to 4 1/2 in the part not so affected by weathering.
The stones can be worked with any hard material such as bone, shell, obsidian, etc., and naturally, by any prehispanic metal implement.