Was this manuscript supported by ANY NIH funds? AND was it subjected to Peer-Review (not subject to editorial review alone)?
The US Federal Government has passed a series of laws and regulations requiring that research funded by tax-payer dollars be available to the public. In practice, the result is the set of Public Access Compliance regulations that must be followed. Almost all of the papers published at CSHL are subject to these regulations.
Any papers matching these three (3) criteria must address Public Access Compliance:
Given that April 2008 was over a decade ago, it is safe to assume that criteria #2 is met for all future publications. Therefore, if you are a researcher or scientific administrator acting on behalf of one, and the manuscript you are dealing with was funded with any NIH funds, and was peer-reviewed, you MUST address Public Access Compliance.
One area where this guidance can be unclear is in the case of review articles. Many review articles are not subject to peer review, and only undergo editorial oversight. If you are unsure in the case of your particular paper, please contact the editor at your journal to determine the answer.