The domed hubcaps do not fit the 66-7 slotted wheels. I'm guessing these may have been fit by installing OG style pre 65 clips to the newer wheels to hold the hubcaps on. I think they are the same dia as the 66-7 hubcaps. However if that was an easy mod, I wonder why guys abroad do not do it everyday??
Other possibility may be that these are Porsche 356 wheels?