vc-rcs-master-templates

vc-rcs-master-templates is a variable defined in `vc-rcs.el'.
Its value is

("%sRCS/%s,v" "%s%s,v" "%sRCS/%s")

Documentation:
Where to look for RCS master files.
For a description of possible values, see `vc-check-master-templates'.

You can customize this variable.