Mystery/adventure novel, statue with hidden nook for leaving notes?

[Erin]

Sometime in the 2000s or 2010s I read a (US) Reader's Digest magazine, and a short anecdote from one of the humor sections fascinated me. The writer said he/she had read a mystery (or action/adventure, spy/espionage, or...?) novel in which a character had hidden something important in a nook of a statue that was on public display. The anecdote writer later had a chance to visit the real-life statue, and discovered it even had a hidden nook as described in the novel. Reaching his hand inside, he extracted a note that humorously said, "Good book, wasn't it?"

Finding the RD issue again wouldn't help much, as the novel title and the statue's name/location were not mentioned. Though if I'd have to guess, the issue was published sometime between 1985 and 2010. (I went back a few years because most everyone in my family kept their back issues of RD since they're timeless.)

I'm more interested in the book itself, although there's also the chance that the anecdote writer made the whole thing up and neither the novel nor the statue exist. Thanks in advance!

[Tab]

It looks like the anecdote was in the "The Reader's Digest - Volume 130, Issues 777-782 - Page 127" from 1987.
https://www.google.com/books/edition/...

There are only tiny snippets that can be seen on Google Books,
like this one

While the book was not mentioned in the Reader's Digest, it is start.

[Erin]

Oh, wow! That is indeed a start, since at least now I know it was a spy novel. And on a sentimental note, if it was an '87 issue it was probably at my late grandparents' that I read it, since they were the relatives with a shelf full of older issues.

Thank you!