When was the 35th MA monument dedicated?

I just made an exciting find. The building in Massachusetts where the 21st Massachusetts monument (that sits by Burnside Bridge) was made is being torn down. The sculptor's papers and photographs made it into my collection this week and I am very gratified and excited at the find. It even comes complete with O.T. Reilly graffiti, which is especially timely because I think I have decided to call my next book "Rare Images of Antietam Through the Eyes of O.T. Reilly."

Anyway, when I was trying to date these new photographs, I got to thinking about the dates the monuments on the bridge were dedicated. The first monument on the bridge was put there in October 1887. For some reason the park, on their website, has it being dedicated in 1906. Well, they can't be perfect.

The 21st MA monument was dedicated on Massachusetts Day in 1898, the same day as the Massachusetts State Monument was dedicated near the Cornfield. But the strange one is the 35th MA monument. All the sources I see simply say dedicated in 1898 with no date. John Shildt goes the farthest in his book Monuments at Antietam and says that it was probably dedicated on the same day, but does not give a cite.

I want to put the story about this sculptor in my next book, the O.T. hook being that his photos were taken when O.T. had graffiti on the bridge (I know, a tenuous link, but if you don't like it, write you own dern book.) So I think I will try to solve this mystery. If anyone has any info I would love to hear it. It is not a big, compelling mystery, but maybe I can use the hunt as an excuse to go to Massachusetts and get my portrait taken by David Bachrach's grandson. I spoke to him on the phone while getting permission to use some images and he is not only a really nice guy but he had some very interesting things to say about the Civil War.