Yes,
These 15" are rare and the original Mercedes did have the steel inserts, I believe Ronal made the originals. I had two sets over the years. One set had the standard factory asto-silver with clear finish. The other set is still on my 300SE sedan and has the astro-silver centers with polished aluminum outer rims with clear coat.
both sets were the original bundt stlye.
Joe Alexander
Blacklick, Ohio