New...and confused

[Robert Brush]

Hi and Thank you for welcoming me to your site! From what I am seeing, there seems to be a number of very knowledgeable folks here....which brings me to my state of confusion.

I have an old Parker which I haven't been able to find much info on other than the ser. no is 17043 and made in 1879. I cannot for the life of me figure how to separate the barrels from the reciever so that I can get a better look at the insides. There is no actual beaver tail to remove, but rather a metal handle which moves sideways to allow opening of the breech. It appears that it is pinned in place. I am attaching only 1 photo as I tried attaching several, but I guess they are too big a file or something...I am not real computer saavy either.

My wife has had the gun passed down to her and she has no history on it, other than it's old. Can anyone shed any light on this gun? Is it valuable or should I not worry about keeping it in a safe?

Thank you in advance for any assistance/info you can give.