To what extent were/are any of the Confederate statues/monuments currently being debated funded or erected by white supremacy organizations?

Someone made a post on r/politics stating they were a museum director and gave this piece of non-cited information:

the overwhelming majority of these statues were mass produced and of completely shitty quality, and farmed out to dozens of municipalities in the 20th century as both anti-black monuments and fundraising tools for "white pride" groups like the KKK or the Daughters of the Confederacy.

Do we have any books, articles, primary sources on this part of our history?