That works great if your environments are on different systems. All you have to do is move your scripts over from one environment to the other and they should work immediately if perl is in the same location (such as "/usr/freeware/bin").
But what if you have your staging environment on the same system as your test environment? It seems that there would be a few decisions to make. If separate copies of the same version of perl must be maintained for some reason (i.e., for backup or other portability issues), then installing perl in a default location such as "/usr/freeware/bin" may not be good.
It seems that you would want to set up separate directories, one for test, one for dev, each containing an installation of Perl. For ease of switching between versions, you could either change the symbolic link "perl" to point to your desired version, or alter the #! line in every script when rolling them from dev into test. Neither of those seem to be great options.
I'm not offering solutions, here, just points to consider. Perhaps someone else has gone through this and has a much more efficient solution.