Military Indians came in four basic models. The smallest and least expensive, is the 741B, which is a 30.50 cubic inch (500 cc) twin based on the Jr. Scout, which is usually the model you will see for sale, due to the higher production numbers. 

The next model is the 640B, which is the 45 cubic inch (750 cc) Scout 
based model. This one starts to get a little tougher, because of the lower production numbers. 

Next step is the Chief, model 340B. This one, is basically a civilian model, 74 cubic inch engine (1200 cc), with some Military changes. Again, not a real high production model, but most items are accessible. I've seen figures estimating around 5000 units built. 

Last but not least, is the 841, which is the toughest to find parts for, since these were a limited model, of an all new design. They sported a transverse 45 cubic inch  (750 cc) V twin engine (Moto Guzzi Style) and a shaft final drive. Many of the parts for this bike, are extremely difficult to find, as the total production was around 1000 units, and it is the only model of the four which was not an adapted civilian production bike. 

The first thing people usually tell me about the Military bikes, is that they must be easy to paint. Yes, and No....... The application is fairly easy, but you will have as many, or more hours in the paint, as you will with a civilian model. The reason is, sheer number of parts. Each Military bike will have around 120 to 150 individual pieces to paint. A civilian model will have more chrome, or cad plating, and the finish paint items usually consist of the sheetmetal parts that number around a dozen or so pieces. Several of the less obvious parts such as frame, hubs, forks, etc. are either painted black, or powder coated which breaks up the color scheme. Take a look around your shop, and try to imagine 150 parts hung up to dry, at one time...... 

Research information is sometimes very tough as well. There are a few 
books with photographs, but lets face it, it's more glamorous to feature a flashy skirted fender Chief than an olive drab Military model. There are reprints of the manuals, and parts books available, but if your bike is missing a bunch of parts, you will have a tough time determining what's missing, due to the lack of exploded view drawings, and details. If you solicit opinions about finishes, you will get at least one for each person you ask. Which items were cad plated, painted, parkerized, etc., etc..... What shade of olive drab is correct? Well, I have my opinion too, but I won't guaranty the accuracy of anyone's opinion. My approach has been to find a part that is original, and exposed to as little sun, and abuse as possible, and have the paint matched to it. Old spare parts were packed in Cosmoline, and it's my belief that this made them darker, so I prefer to check things like the inside of an original tail light. This will give you the least disturbed example of original paint that I have found. 

The next item to think about is parts availability. If you want a correct (or close) restoration, you are probably going to have to locate some parts. Well, here is a bit of a problem. Many of the Military bikes were sold as surplus, and at the time they were cheap, so they had the original hardware stripped, and discarded. There are a few spares around, but you have to dig pretty hard to root them out. There are maybe a half dozen dealers around the world that have any significant supply of original, and reproduction parts for the Military Indians. Several NOS or used parts will turn up with individuals, but again, you better get out the shovel! 

Once you are done with the research, and parts gathering, the repairs, 
and rebuild are fairly straightforward. When done, you'll own a unique bike, that will draw just as much attention as the skirted  bikes, but they don't have the mass appeal when it comes to resale. When most people think of an Indian, the skirted Chief will come to mind, so you should expect the "nice Harley" comments. 

I got into Indians because of the sameness of the Harleys, and the 
Military models keep me away from this issue with Indians. My first Indian was a 1948 skirted Chief, but it is probably the last skirted model I will own. I still love the skirted models, but I tend to want to be different than the masses (Lemming theory, ya know). I also feel that the Military models represent the great contribution that motorcycling made to the world in a time before the negative image of motorcyclists portrayed by the outlaw bikers, media, movies and the invasion of the "crotch rockets".