I too have some doubt, but it's not a 508 C: just incredibly similar.
The same photo appears in a feature on L'Auto Italiana (if I'm not wrong) about Savio history in the late 30s and the date in the caption is indeed 1934 (but, not being a contemporary report, it could even be a mistake).
In fact, I have always thought 1934 would probably be 1935; hard to suppose Savio to be in advance compared to Fiat and Mario Revelli to propose that aerodynamic shape.
But if you consider that the 508 C/1100 is just an adaptation of the 1500 shape on a shorter wheelbase, you can understand how a so similar result can have been achieved independently also by Savio a couple of years before (Fiat 508 C was launched only in 1937), but I cannot believe they made it before seeing the 1500 (unless they have seen a prototype already in 1934).