Nah, Blumels have an aluminium layer too, but in my experience they are weak and prone to cracking. They have a round cross section as opposed to the Chromo's box shape, no stripe pattern or rear reflector, and the stays are thinner. I have also read that the Chromos have stainless steel fittings, but I can't be sure that the Blumels don't.
Once I went through 2 pairs of Bluemels, both cracking in the middle of the rear guard as well as cracks appearing near the brake mount, I got them replaced with SKS Longboards which seem to be much more durable as well as providing far better coverage than either the Blumels or the Chromos.