I think the term 'sealing' is being used in two different contexts here: shrink wrapping the jacket a/k/a a 'sealed record' and some sort of sealing agent put on the vinyl. I am unaware (not that I'm the last word on any of this) of a coating being put onto new vinyl to conceal pressing defects, but am certainly aware of used records being treated with all kinds of stuff to make them look clean. One of the many reasons cleaning used vinyl is essential-- to remove the residue of prior 'cleanings'-
As to concealing defects, there are some papers on file at the AES that discussed the value of carbon black being used not only as an anti-static agent, but concealing 'plate out' issues in pressing.
My take on the mold release agent is that it is over-hyped as a problem. I do think a lot of brand new records are dirty, but that's because of the environment in which they are made and the handling of them before they are finally sleeved and jacketed. Some of the inner sleeves used don't help either.
I do clean 'new' records whether or not they appear contaminated or have any paper flecks or other detritus from handling.
As to concealing defects, there are some papers on file at the AES that discussed the value of carbon black being used not only as an anti-static agent, but concealing 'plate out' issues in pressing.
My take on the mold release agent is that it is over-hyped as a problem. I do think a lot of brand new records are dirty, but that's because of the environment in which they are made and the handling of them before they are finally sleeved and jacketed. Some of the inner sleeves used don't help either.
I do clean 'new' records whether or not they appear contaminated or have any paper flecks or other detritus from handling.