A couple other people have run into problems repeating things with surround.vim:
In the first link, there is a quote from the surround.vim docs that implies visual mode surrounding doesn't work:
The "." command will work with ds, cs,
and yss if you install repeat.vim
And given the text elements surrounding it, I don't think there's a way to surround just the #005462 without using visual mode.
So for this particular problem, I think a quick, repeatable search and replace is your best bet.
:s/: \(#......\);/: <code>\1<\/code>;/g
Go to the right line, and type or paste this in command-line mode and press enter.
Move to the next line and press &
to repeat it.
If you know you want to replace ALL of them in the file, you can add %
before the s/
command, like so:
:%s/: \(#......\);/: <code>\1<\/code>;/g
Hope this helps!