When a writer acknowledges working for the company that makes a product that he or she has been reviewing or talking about, the acknowledgment most certainly is a disclosure, which Merriam-Webster's Eleventh Collegiate Dictionary (2003) defines as follows:
disclosure n (1567) 1 : the act or an instance of disclosing : EXPOSURE 2 : something disclosed : REVELATION
where disclose can mean (according to MW) "to expose to view" or "to make known or public," as in
Full disclosure: I work for the company that makes this product.
When a writer acknowledges not having tested a feature of a product being reviewed, it seems to me that disclosure is once again a suitable word to use in describing the acknowledgment:
Full disclosure: I never actually tested this feature I'm telling you about; all of the information I'm passing along comes from a company press release about the product.
But the situation changes when the writer says something like this:
I never actually tested the product's acid bath feature, so use it at your own risk.
Here, the author's statement serves as both both an acknowledgment of not having fully tested the product (a disclosure) and a declaration about not accepting responsibility as an endorser of the product if the reader uses the product's untested feature and bad things happen (a disclaimer).
The Eleventh Collegiate Dictionary's entry for disclaimer notes several possible meanings:
disclaimer n (15c) 1 a : a denial or disavowal of legal claim : relinquishment of or formal refusal to accept an interest or estate b : a writing that embodies a legal disclaimer 2 a : DENIAL, DISAVOWAL b : REPUDIATION
The terms denial, disavowal, and repudiation have in common an overt refusal to acknowledge or accept responsibility for something; indeed, they amount to an assertion that the person or entity making the disclaimer is thereby absolved of responsibility on any theoretical grounds whatsoever.
An example of a disclaimer that isn't a disclosure would be something like this:
Disclaimer: Although the tablet survived my rock-throwing test without sustaining serious damage, your results may vary—and I will not buy you a new tablet if you break yours.