It's possible, but not exactly easy. For a time, the new format was only available using the log destination "telly_prototype_console" with something like this in puppet.conf:
[main]
logdest = telly_prototype_console
However, in commit 537343d we replaced the default destination named "console" with the telly console. Unfortunately, we didn't leave the old destination in place as an option, but I'm not sure if we could have.
If this really bothers you, you might be able to create a new destination using:
Puppet::Util::Log.newdesttype :puppet27_console do
...
end
You can see the Puppet 2.7.19 console formatter here:
-Jeff