No. I've never seen a lawyer sign a document as the "custodian of records" in the first instance. That's just odd. And I have never signed off on whether complete documents have been produced--my client does that. And that's for legitimate organizations who aren't criming all over the place headed by pathological liars. First, I would never certify to anything I don't have personal knowledge of. I have no way of knowing whether a complete response has been produced. Someone who works with those records specifically and has actual knowledge that complete records were produced has to sign off. Second, if there was something not produced, and in my case it would almost certainly be an inadvertent error and not something like trump is doing, it would turn me into a witness against my own client. I would have to testify as to why I signed off on completeness when it wasn't complete, whether I lied, who misled me, etc.