Not a very often used term but correct. An alternative could be "kirjojen tukkukauppias" (wholesaler for books), which is not quite so "constructed".

In legal English or business English wholesaler often refers to a company rather than to an individual business person, which is why the preferable term in Finnish is kirjatukkukauppa ('book wholesale business') rather than kirjatukkukauppias ('book wholesale merchant').

The short form kirjatukku is also used to refer to this type of business.

Although it is a good idea to use Google and other similar sources with care (read: with a reasonable amount of deliberation and common sense), it is indicative that Google only finds some two dozen instances of kirjatukkukauppias while the number of results returned by a Google search on kirjatukkukauppa is over 15,000. For the short form kirjatukku the number of results is some 150,000.