Rostyle wheel cover 'dummy' nuts - do they unscrew?

[Triumphtr250nut@aol.com]

Hi Listers

I have obtained some Rostyle covers that have had the hub clips on the back 
removed. The front covers are better than the ones on my car at present. Does 
anyone know if the ''dummy' nuts will unscrew or are they permanently fitted? 
If they do unscrew - is there a special tool?

Regards

Phil Horsley
TR250 1967