It doesn't look abused to me, so may make a fine shooter.
Prices, have just gone crazy lately, I don't think $700 is all that bad. You could have a very long wait to find one in as good a shape and cheaper. They are out there but people are parting them out to make more money.
A couple of months ago I sold my two Erfurt shooters for $500 each, they were buffed/sanded to death guns with almost no finish left of the cold bluing that was once applied. They sold very quickly; sure I only had $400 and $450 into them and made a little money but I think I could of made more. Now I am without a shooter luger and am faced with much higher prices to replace them.
Do you have access to the gun?
Make sure your getting an action that is not binding, the barrel looks replaced to me and that is good for a shooter but if they twisted the frame getting the old one off, it will be a pain to get it straighten again and cost you more dollars.
Get a return policy.
They are not going to let you shoot it, but you will be able to quickly tell if there is sever binding by cycling the action by hand and inspecting for internal ware.
My two cents worth
Vern