There are a few agencies, one in Woodbridge in particular, who never have their sellers fill out a sellers disclosure when listing a property. Sellers disclosures are not mandatory in NJ, and many homes sell without one.
A disclosure it the preliminary information you get from the homeowner, to the best of their knowledge, and is not necessarily the be all to end all as far as the presence or absence of possible defects in the property.
The home inspection you pay for is another tool to help you determine any issues that may be present, or look like they were there previously present/remediated (like water in basement, leaky roofs, etc).
If you are working with an agent, ask him/her about their experiences selling homes with and without a disclosure.
I personally have sold many homes WITH a disclosure that, after inspection, have had items turn up that weren't on the disclosure.
Again speak to your agent and your attorney about the possible down side of not having a disclosure and what can be done to protect you in the event you do decide to make an offer on this home. I wouldn't completely use the lack of one as a reason not to purchase this home.