I don't know anything about Speed Concept skewers. But, they appear to be Trek and purport to be designed with aerodynamics in mind. I see them for sale ~$30

They are steel axles and their weights are not listed anywhere I could see. That tells me that nobody cares about weight &/or their weight is considered a detriment...or at least a negative.

I think you could do worse. They're free, right?