Unusual looking C96

[clevolver]

I have wanted a C96 since I was a little kid, and recently learned of one available locally for sale.  I do not know the seller personally, and they claim not to know much about the gun, having obtained it recently through inheritance.


I would be interested to buy but only if I can determine with certainty the value of the piece. I don't mind if it a desirable gun to a collector or not, and would almost prefer a shooter to a collectible. 


A few notes:

• It does not come with holster/stock or tools.
• It appears to be refinished.
• The barrel is unusual. It looks longer than a typical C96, and the front sight is not of a type I have seen before on a C96. Can anyone identify this?
• The hammer is unusual, with a larger than normal loop.  I have seen this before, but do not know the significance.

Questions:

• How can I tell if this is a genuine Red 9, as opposed to a re-chambered gun or an imitation/counterfeit.
• How can I tell between a C96 chambered in 9mm Mauser vs. 9mm Luger?
• How can I assess the mechanical condition? What do I need to look for?
• Are there any other distinguishing features or marks that I should look for in order to identify which variant it is?
• What would a fair value be, assuming it is in fine mechanical condition?

[1914mauser]

It is not a red-9, it has been re-barreled, re-blued. It has a large ring hammer. It has "0" collector value and is worth around $500 if it shoots/functions well.
Regards,
 

[Bigboy99]

It is very interesting how someone took a rare Von Lengerke & Detmold marked C96 and turned it into a non-collector value C96!