I have one exactly like the one in your second picture.
Unfortunately, I really don't know that much about them. Your best bet would probably to locate a copy of the Flayderman's guide for some basic information on when they were made and how much they're worth.
"The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza
Baby Jesus cries when the fat redneck doesn't have military-grade firepower.