The so-called second site is an add-on which appeared later. There is disagreement if it was multiple ufos or just one. The "bodies" were probably just crash test dummies found in the desert. Yes, the crash test dummies were a couple of years later, but if you are asked questions about 1947 in the 80's and 90's, how can you remember exactly when you saw what? The first crash site was not very impressive (the material was flimsy and had some balsa wood like sticks with some tape with strange symbols - which you could find on tape sold during that time...), so the "second site" was a lot more impressive: dead aliens, big spaceship, etc. What people are recalling as a single event is actually a mixture of several events that occurred in different years.