[mothered]

Yes exactly that

“Non receipt of goods disclaimer form”

Similar to this?

In particular, does It state "I believe the above declaration Is true to the best of my knowledge and belief", or something to that effect?

Then It's fine to go ahead and sign It, namely because It's "true to the best of my knowledge and belief".

In other words, that's what you believed took place to the best of your knowledge. Whether It's right or wrong Is Immaterial.