[css21] is 'initial' a valid counter name?

CSS2.1 spec [1] says:

<css21>
The keywords 'none', 'inherit' and 'initial' must not be used as counter names
</css21>

However 'initial' appears to be a valid counter name in all browsers except webkit.

Now that we have resolved that flowname is an ident, I have a few questions:

*         'initial' was not a keyword in CSS2.1. Was it a forward-looking extension? Is it still relevant?

*         How normative is the CSS2.1 text? Does it actually mean that the value is invalid, or is it just discouraged?

*         Should 'initial' also be invalid for flow names, in addition to 'none' and 'inherit'?

[1] http://www.w3.org/TR/CSS21/generate.html#counters