There are a few books out there. Can't recall titles to save my life. Go to the sports section of Boarders or Barnes and Nobile. They have books like that. Plus it's a bit funny to go to checkout at the registers with a book on guns or hunting and see the look on the face of the bleeding heart lberal working the counter
It still depends on condition, time of manufacture and markings. Get a copy of Fjestad's Blue book of gun values. Also reference Luger Tips by Michael Reese. Best way is to have an appraiser look at it.
When it comes to scent, there are basically two types; those that attract and those that mask. I've tried both on many occasions. There are lots and lots of "doe in heat" scents, designed to attract a big buck into range. I've also used a "cow in heat" scent while elk hunting.
Another scent would almost be better named as a "coverup smell". The main goal is to cover up human odor or mask it. Though I don't believe you can ever totally eliminate all human...