Mystery writer Lindsey Davis (and Faldage?) doesn't seem to understand the nuances of her title. The pertinent attendant connotations are...

The Silver Pigs: = particular silver pigs. Turn your head... see the silver pigs.

Silver Pigs: = General, symbolic, silver pigs. Ah...
And sup till time and times are done
The silver pigs of the moon
the silver pigs of the sun.

Sometimes writers fight stupid fights. I bet her books are entertaining but hardly high art. The title “ The Silver Pigs” is a bit heavy-handed if that's what they meant, but she should be happy that american publishers wish to mislead the depth hungry american book buyers by suggesting the heavy for the light.