Amazon must be making up their own numbers.
Linaro project never released a 4.5.4 gcc.
https://launchpad.net/gcc-linaro/4.5/
The most recently released 4.5 is based on: GCC 4.5.3+svn184976
Back in March, 2012.
https://launchpad.net/gcc-linaro/+milestone/4.5-2012.03
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But in answer to your question - yes, some people noticed.