British Contract PP .22

Greetings all, just found this forum today and as a long time
Walther fan it looks like I'll be spending some time here.

A few weeks ago I bought a .22 cal. PP. It has a black painted
finish with many paint chips and scratches. I wanted it for a shooter and trail gun, and the price was right so I bought it.

Researching it's history I find it's a British Contract PP as listed
in Dieter Marsehall's book Walther Pistols, on pages 33, 34, and 35. FYI, this book is full of info on older Walthers. It looks
exactly like the picture on page 35 but does have a small
Interarms import stamp on the right side of the frame.

My question is how valuable is this pistol? I'll probably never
sell it, she shoots great, but is a little ugly and I'm thinking
of having it reblued. I don't want to ruin it's collector value,
if there is any, by having it refinished.

For my first post I've rambled on long enough.  

                Thanks guys. what do you think?