What purpose does "The Custom House" seem to serve?I need references from the story to prove my point

I think Hawthorne does this to prove he has gone to great
lengths to research for his writing before he put it in context. He hopes to validate
and give credibility to the expertise he has in creating a historical novel for we the
readers.

The Custom House he spent time in had stacks and
stacks of old papers and records. One item he found in particular gave him great
motivation for the book:

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But the object that most drew my attention, in
the mysterious package, was a certain affair of fine red cloth, much worn and faded.
There were traces about it of gold embroidery, which, however, was greatly frayed and
defaced.

After revealing that
this displayed a particular letter 'A', the author later notes that he found more
twisted papers that gave explanation for the letter:

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There were several foolscap sheets containing
many particulars respecting the life and conversation of one Hester Prynne... prying
further into the manuscript, I found the record of other doings and sufferings of this
singular woman.

The
sufferings and doings he learned of give credence to Hawthorne's account entitled
The Scarlet Letter. He is trying to point out with the Custom House
that he journeyed and learned about the real life person who was
Hester.