Looks like brushed steel to me. We normally specify zinc post-plated CRS with a specific grain direction for this sort of chassis if it isn't painted. This helps with the fingerprints but I still recommend specifying that it be protected with the thin adhesive poly sheet during processing and even shipping if possible.
In the mid-1990's we worked with a material from Triumph Industries called Tri-Clear. It was a burnished EG that resisted finger-prints. Unfortunately, the process was a proprietary process at the time, and there was only one supplier for the material. Most of our customers began to transition from the Tri-Clear to G30 with a minimum spangle.
