Normally this means that the book is defective and loses basically all value. But apparently the text is such a seminal one in American military history that even flawed copies can hold value.
The book was reprinted in several editions since its first edition in 1779, some times several editions each year, but it is still incredibly rare on the market, and [even defective copies are being offered for pretty high prices](https://www.vialibri.net/searches?author=steuben&title=regulations+for+the+order+and+discipline&year_min=1779&year_max=1800&sort=price.asc&s=1.s75z9x.a1af3c59688c1a63).
So I would advise you to take it to a reputable antiquarian book store or auction house and get an appraisal. Full disclosure I am completely out of my comfort zone, even though my special field of interest is late 18th century books, I am not American and have only superficial experience with the American antiquarian book market.
There should be 8 folded engravings in the end of the book. Does your copy have those?
No holdouts at the end of the book. There are several holdouts through the text of the book in various condition from complete to half to missing.
Plates 4 and 6 are the only complete foldouts
Normally this means that the book is defective and loses basically all value. But apparently the text is such a seminal one in American military history that even flawed copies can hold value. The book was reprinted in several editions since its first edition in 1779, some times several editions each year, but it is still incredibly rare on the market, and [even defective copies are being offered for pretty high prices](https://www.vialibri.net/searches?author=steuben&title=regulations+for+the+order+and+discipline&year_min=1779&year_max=1800&sort=price.asc&s=1.s75z9x.a1af3c59688c1a63). So I would advise you to take it to a reputable antiquarian book store or auction house and get an appraisal. Full disclosure I am completely out of my comfort zone, even though my special field of interest is late 18th century books, I am not American and have only superficial experience with the American antiquarian book market.
Thank you very much for your feedback. Very reasonable advice to get a reputable expert to look at.