The Lido would already have been in the Public Domain..."free to use"...even if the Copyright Clause (BIRDIE ACT) had been in effect when the work for Mr. Keiser was commissioned. Nothing in the proposed act that expands protection to golf courses will apply to classic/older course designs.
But...imagine if Macdonald were living a dew decades after creating the original Lido. I think most here would feel that he should have the right to re-build it somewhere else at his discretion. Let's say someone came along and carefully had measured the original Lido, and then copied it in most every detail. Not right, which is what the new act will prevent moving forward.
Nothing now prevents someone from flying a drone over Streamsong, capturing all of the topography in digital form, and then rebuilding it in California. Streamsong's only recourse would be Trademark infringement (the name and logo), and perhaps some very hard to prove "trade dress" items. Nothing now protects a completed course designed by a modern GCA.