But I don't see anything about GWT Designer which I don't think is part of the SDK.
So I wouldn't say that Google dropped support for the old versions of GWT. But you do have a case for saying that support for old versions of GWT Designer has been lacking or apparently does not exist.
No one at your company has a copy of an Eclipse install with the tools configured for that product?
Lots of things have changed and been deprecated (for multiple releases/years) since GWT 1.7.1. That sounds like quite a project you have ahead of you. Good luck!