Jigsaw puzzles are always a risk...let's face it; what are the chances that the whole thing is really there? There's no way to tell, save standing in the store and counting pieces (and I saw an old lady doing that one day)...but I'm not gonna do that.
Lots of factors go into me buying an item like this. First, it's so obviously from the 1950's'; secondly, it has that art style that makes it unique to the time; thirdly, Western-themed items are just not something you see anymore. The last thing I do is examine the box. If it's in good shape, and if the pieces are clean and not damaged, then there's a good chance that, if somebody took care of it, it's all present. And it was!
I didn't even mention that someone is smoking (even though that is a fact of history, and in this case, culture). 100 pieces is the right amount for a leisurely puzzle to do in one sitting. I did learn something interesting about Built-Rite though. They made tons and tons of puzzles, and I began to notice that some pieces were cut in a bizarre fashion...this is because they liked to sneak in some recognizable shapes!
That was an unusual and fun discovery. It's nice that in all the gazillion puzzles that have been made over the years, one company was at least having fun with it.