Is this an unambiguous CFG that is not LR(k) for any k?
Just as a slight nit, those aren't $LR(1)$ item sets, because they don't include the following terminal symbol
With that proviso, your reasoning looks good to me. Of course, the language is not inherently nondeterministic because you can rewrite $B$ as:
$$B \rightarrow \epsilon\,|\,Bbb$$
The palindrome language $L = \left\{ w w^R\,|\,w \in \Sigma^* \right\}, \left| \Sigma\right| &gt; 1$ is the classic example of an inherently nondeterministic language. There exists an unambiguous grammar for $L$, but there is no $LR(k)$ grammar for any $k$.