Library availability is so hit-or-miss. My library's digital selection is terrible for this genre, but my friend's in a bigger city has everything. If yours doesn't have it, you can sometimes suggest a purchase through the Libby app! I've had a few requests fulfilled that way.
Is there a YouTube channel or snippet where the narrator discusses his process for this book? Some voice actors do interviews or behind-the-scenes videos where they talk about character choices and challenges. I find that stuff fascinating. It adds another layer of appreciation for the final product when you understand the thought that went into it.
Hearing a narrator break down how they approached the werewolf's internal monologue versus the system's automated voice would be cool. If such content exists, it might help potential listeners decide if his interpretive style aligns with what they're looking for.
Compared to the big studio audiobooks, this one feels more homespun, but in a good way. It's a single narrator giving a straightforward reading of the text. There's no fancy editing or cuts for time. It feels like a full read. I enjoyed it. The cliffhanger at the end of the audio made me immediately buy the ebook for the next part, so mission accomplished for them.
I haven't come across any evidence of bonus chapters. My method is usually to compare the 'Length' or 'Runtime' listed on the audiobook store page with the page count of the ebook. If the runtime only accounts for the main text, no extras are included.
In this case, the math checks out for the core story only. Any significant bonus material would add noticeable time, and that would be advertised as a selling point.