Yes, they repeated the first verse and coda at the curtain call and it did ensure a standing ovation, but you're right about the song coming out of nowhere at the end of the show.
I know they are trying to posit that the events of this musical are what inspired the hymn, but was written like 20, 25(?) years after the events of the play, so while they may have influenced the writing of Amazing Grace many other things could have as well.
This is no Sunday in the Park where we get to see a creator at work. We never see Newton write a single note of any hymn. It's just tacked on at the end because this guy happened to compose a famous song years later.
On another note, they need to comb through the book and take out some of the anachronistic jokes. For example: after an attack on during a slave auction one of Newton's men looked out at the audience and sarcastically deadpanned, "Well, that went well." Not only did it fail to get a laugh, but it felt horribly out of place with the milieu and tone they were trying to establish.
RippedMan, I wasn't impressed with the design elements, although some of the women's costumes were pretty. There were these massive wood panels that slid around the stage, sort of like the panels used in Bonnie & Clyde. Chairs, a table and/or piano and crates would be tracked out from time to time. There were very few actual set pieces.
Along the two sides of the proscenium there are two crow's nests that were used when they were on the slave ships. Unlike the more impressionistic ship at the end of The Last Ship, the tried to design a more literal ship, but with perhaps a limited budget maybe the former approach would have been a wiser idea.
Marie: Don't be in such a hurry about that pretty little chippy in Frisco.
Tony: Eh, she's a no chip!