"German 17th century still life": after Georg Flegel, but how recent?

Bassenge, from Germany, sells on 26 May 2017 a "German, 17th century" Still life, estimated at 1,200 Euro.

It is a copy after works by Georg Flegel (1566-1638), the German version of Jan van Kessel (actually, Flegel was the older painter by far, so it would be more correct to describe Van Kessel as the Dutch version of Flegel). Multiple elements are copied almost literally (the frog on the coins, the wasp with the pearl ring, the snail ...) are copied identical but in reverse.

A similar work by a follower of Flegel was sold at Lempertz in 2013 for 18,000 Euro against an 8,000 Euro estimate. The work for sale now is a lot worse though, an the estimate is probably about right, if this really is an old copy. I wonder though, with the reversion, whether it isn't a more recent attempt to make this copy after Flegel harder to detect? It is painted on metal, which again makes it harder to date, and it has the bee of the Lempertz one in reverse as well.