For Rails, "rake doc:guides" generate Rails Guide for 2.2.2 and 3.0.1 but not 2.3.8 or 2.3.10?

Question

I didn't know that the old Rails guide is available by

cd railsproject_folder
rake doc:guides
cd doc/guides

and since our project has been using Rails 2.2.2, so the Rails guides for Rails 2.2.2 can be seen there, because the official Rails guide on web is for Rail 3.0.

I tried that with Rails 3.0.1, and it works too. With Rails 2.2.2, the fonts are not formatted as nicely, so I thought maybe Rails 2.3.8 or 2.3.10 have improved formatting, but using RVM, I try that rake task and it can't run.

Also, the folder

~/.rvm/gems/ruby-1.8.7-p302@rails238/gems/rails-2.3.8/doc

is almost empty, while if it is

~/.rvm/gems/ruby-1.8.7-p302@rails222/gems/rails-2.2.2/doc

then there is a guides folder in it with lots of files. Is there a way to get Rails guide for Rails 2.3.8 or 2.3.10?