Mybe the brass plaque has noting to do with the vanes?

The marble(?) base looks different to the others. Less white marbling as if its from a different block (quarried from another location).

Its a different size to the others as well, which would be odd if they were made as a trio.

The type is different as well between the vanes and the brass plaque. And a different method appears to have been used to engrave them.