I see what you are talking about Wilber. I cannot speak to a specific regulation, however with the wide veriaty of ways I have seen the jackets worn in period photos. I would hypothise that if there were they were not strictly followed. I do know that generally on military dress all buttons are supposed to be buttoned (at least in the modern Navy). Looking at the Generals choice of buttons to leave undone I would suspect a couple of reasons.a.) he contemplated going for the Napolean look in the photo,changed his mind forgiting to button it back.b.) The Jacket is a little snug on him and leaving every third button loose helps him breathc.) his accouterment straps etc pass along those areas and get snagged on those darned muffin top buttons; leaving them undone solves this.d.) He was wearing it open when he got there the photographer sugested closeing it for a more martial apperance; he hurridly and somewhat adjitatedly complied.Just a few thoughts.........