Does Google expand searches to include terms in first results?

Nope - what you're seeing is the result of an out of date index.

Things to notice:

1. The dates in the results. Notice that they're from September.
2. One of the results clearly displays the barcode in the description. In other words, at some point the website did provide it to Google's spider.
3. A direct search for "Faolan O'Connor Drawing Dead" brings up 2k+ results. A search for the barcode only gives those 4. If Google had related them, you probably would've seen at least some portion of those 2k results.

Can I see what Google did?

Yes - click the little green arrow then click on "Cached":

Then click the 'view source' button and you'll see that in both instances, the barcode is discoverable somewhere on the page itself:

In one result the barcode is visible directly on the page; in the [PDF] result, the barcode can only be seen in the source.

Yes, Google does expand search terms...

Google associates and pairs words, numerals, misspellings and non directory words with a vast amount of search terms and they need not be an 'exact' search. For example Conor McGregor is also know as "The Notorious", those containing the exact are generally preferred but not always, many pages will be about Conor McGregor and include no mention of "The Notorious", this is because Google trys to display results it thinks the user wants..

So... because Google has discovered Faolan O'Connor's with the code 683422223143 on the same page it has associated the code with that search.

Even this answer informs Google that 683422223143 is to be associated with Faolan O'Connor's book.