Rocksmuk album - bootleg or not?

Rocksmuk is a 1972 Dutch LP which has been of interest to many Rock'n'Roll collectors because it included not only well-known hits, but also interviews with Chuck Berry, Bo Diddley, Carl Perkins, and Jerry Lee Lewis.
For many years this interview was found only on this rare album until it surfaced on several bootleg LPs and CDs in the late 1980s and 1990s. Because the original Rocksmuk LP contained hits from the Chess and Sun labels, most collectors saw this as a bootleg as well. As such it is listed on this site and in Morten Reff's Chuck Berry International Directory.

A few months ago, a Dutch reader complained about this classification:

On your site I see that you call this LP a bootleg.
However, it is a legal release from 1972 (not 1973).
One side has the Chess label, the other side has the Sun label.
For both labels the distribution rights came within the same company. By the look of it I guess it was Bovema (now EMI).
In 1972 the book "Pop smuk" (fl. 9,50) was published and this LP is an addition to that book. The book also has the interviews, but of course in print.
Both book and LP were legally widely available in bookshops.

First: Thanks, Luuk! It's always nice to get response from a reader as it shows someone is really reading your stuff.
Following Luuk's comment, I went to find the Popsmuk book he was talking about. It took some months to find a seller, but finally I got it:

The full title of the book is Popsmuk/Het Popjaarboek '72 by Pim Oets/Gijsbert Hanekroot, © 1972 Born nv.
So this proves Luuk's first remark: The book is from 1972 and as the sticker on the cover refers to the LP, that one should be from 1972 as well.
This however contradicts Fred Rothwell's statement who dates this interview to September 1973. Using the book we can correct Fred by quoting Pim Oets: "The interviews in this book have been made between September '71 and September '72 for the VARA radio program of same name [...] The sequence of the presentations is in chronological order." Given that Berry's interview is the next-to-last one, September '72 should be the best guess for the date of this interview.
The book in total contains 27 portraits from Ray Charles to Paul McCartney, each consisting of some very good photos by Gijsbert Hanekroot and some three pages of interview by Pim Oets. Berry's part is an extended version of the interview heard on the album.
The most interesting page in regard to the album is page 137, the next-to-last one. It contains a description of and a voucher for the Rocksmuk LP. As always, a click on this image gives you a better-readable version.

So what do we learn from this ad? First we find a label for the "elpee". While the album itself does not contain any label information other than Chess and Sun, the ad calls it Negram NQCS 1. According to Discogs, Negram was a "Dutch label, which was run by Hans Kellerman. In the late seventies it changed name to Bovema Negram, which was eventually acquired by EMI Holland." Negram indeed produced Chuck Berry records in the Netherlands such as Spotlight on Chuck Berry (Chess SPLO-3) or the Dutch version of the London Sessions album (at least according to Discogs). So here's Luuk almost correct. It wasn't called Bovema back then, but it seems Negram had rights to the Berry material.
Finally the ad contains a voucher on 7.50 Dutch Gulders to reduce the album price from Hfl. 17.50 to "een tientje" (ten). And it says the album is "leverbaar bij de erkende platenhandel", i.e. available in well-known record shops.
Given all that, I must accept Luuk's comments: Rocksmuk is most probably a legal release.