A bit of photo manipulation shows that the takedown lever appears to be strawed.
I admit to some curiosity about the grips. In my experience the Geweermakers School was not very consistent about stamping their work, if the grips are not GS stamped this would not necessarily mean they are not right. The serial number stamping--or lack of same--would be as telling.
The left receiver proof should be stamped 'under' the blue. The highlight effect here is most likely a lighting effect of the photograph.
Going by this single photograph, I opine that this may well be a straight-up piece. Pretty expensive, though...
--Dwight