The 'no import marks' is odd. The legend "Made in West Germany" is required for importation to the U. S. That requirement has been in place since Hec was a pup. The importation marks of 'Imported by [whoever]' has been added to the (likely ATF) statutes sometime after the Gun Control Act of 1968. That law started up the entire concept of Federal Firearms License(ing)
Perhaps the arm was never imported by a business, but an individual. In that case, the arms would be admitted to the U. S. - currently with the assistance of an FFL. Obviously, prior to the 1968 GCA, no FFL existed and the process would have been simpler.
I collect this caliber of handguns; I do not have PPk as I'm too cheap to part with that sort of money. I would happily pay $900.00 for it. I would expect to see a price tag of between $1500 and $2000 on it (subject to haggling, of course) as this is a collector arm. I doubt many folks would want it enough to have as a defensive pistol in that caliber.
I do not want to start a discussion over whether the .32 ACP is proper for such use, but rather there are less expensive alternatives.