Removing a repository merely restricts the sites from which you can (for the moment) download a module.

If the install -- after changing your list of possible sources for modules (ie, removing trouchelle) -- spat no errors or other disappointments, it's likely the install went fine.

So, try it out. That's an imperfect test, since it's possible one element of the 1.6.1 could be borked somehow and still have your test behave well, if it doesn't access the broken element, but if your tests (trying it out) work ok and produce results commensurate with your inputs, you're good-to-go.