I read in Rick's "Pocket Paris" that the Musée de l'Armée is closed the first Monday of the month, but when I went to the website that was not the case (as far as I could tell). I was able to purchase a ticket on June 4, a Monday.
Anyway, it might be worth double-checking websites for times and dates just to make sure your plan isn't thrown off.
Books run from 1.5 years to 2 years to print. You might have gotten an old one.
Google is your friend.
Yeah I know Google and Amazon rule the world lol. For better or worse our time in Paris is Sunday though Tuesday, including the free museum Sunday followed by super dee dooper crowded Mon - Tue. Oh, well.
My favorite way to get hours is Google Maps. If you click on the museum in the map, a side panel opens up that gives information including open hours/days. So far it's been more accurate than guide books, which are often outdated or give an average rather than the hours for the current season. My only gripe is there are still many sights, not so much in Paris, that don't include the information. Google is always asking me for info, but my brain thinks open/not open and rarely pays attention to the hours (unless it's not open).
When I Google the name of a museum on my desktop computer, I often get a side panel on the right with a small photo and map, a link to the website, and some key bits of information. Usually the open/closed status is included, and there's a pull-down that allows you to see every day of the week. You have to go to the website for information about holidays. Of course, the information Google coughs up has to come from somewhere, and I don't know that it's always exactly consistent with the information you can dig out of the official website. It's a heck of a lot faster, though.
