Chuck Berry White Label Record on BARCLAY - What Is This?

Recently I came across a white label EP on French BARCLAY label. Its number is 70668 and you may know it. It's a 1964 Chuck Berry EP containing Nadine and three other Berry numbers.
The first thing you will notice is that this record neither tells you the name of the artist nor any song titles. (The one I have has some handwritten notes on it which are obviously unrelated and added by a later owner. I removed those from the scan below. As with every scan here, click on it for a higher resolution image).
The printed text on this translates to "Sample, no commercial value". The stamped date might be the date of production. I asked around and Morten Reff told me he owns a similar copy, though his is stamped July 1st.
We could not find out whether these records are test pressings produced for internal checks within the record company, or if this is how Barclay marked their promotional copies given to DJs or dealers. If you can add any knowledge to this, let us know by sending a comment to this entry.