You might want to pick up the book "Backbone of the Wehrmacht" by Richard Law. Amazon has it for $69
http://www.amazon.com/Backbone-Wehrmacht-German-Rifle-1934-1945/dp/B000KK29O0/ref=sr_1_1?s=books&ie=UTF8&qid=1405094113&sr=1-1&keywords=backbone+of+the+wehrmachtIt helps a lot in identifying all kinds of 98k markings. The "zig-zag" mark you are referring to
IS an SS rune. It signifies that the rifle was built in a concentration camp under supervision of the SS. "bcd" identifies it as being built by Steyr-Daimler-Puch AG in 1942. You may find "Deaths Head" and other SS marks under the wood in various locations and also possibly on the stock. Although if the stock is not original to the rifle, that is not likely. The single rune mark and the deaths head are popular forgeries that are put on 98k rifles to increase their value. But since yours is a Russian capture, it is doubtful that is the case.
Again, ANY 98k owners should pick up the book "Backbone of the Wehrmacht". It has excellent pictures (black and white, but VERY nice close-ups) and gives a great story of the production and use of the 98k. It's the "bible" of the 98k owner/collector.
May I ask...where did you buy it and how much did you pay? Don't be embarrassed about the questions. There are many among us who have paid too much for a rifle. If you like it, price really doesn't matter.
If you plan on shooting it, be sure the ammo you buy is NON-corrosive. A lot of cheap, surplus ammo is also corrosive. While it's not real difficult to clean after using it, I am not a fan of pouring water down the barrel.
Privi Partisan sells non-corrosive 8MM ammo and it is pretty reasonable. Shop around online and you will find it. You can use a website like AmmoSeek to locate online sources.
You will find that recoil is stout, but not unbearable. Cleaning and maintenance is like any other firearm. I use Hoppes #9 to clean out the crud and fouling in the bore. Then use a good gun oil, I like Tetra, but any oil is pretty good. Do NOT use WD40 on ANY firearm!!! It gums up over time and is a real pain in the butt to clean off.
That's about it. Since it's a capture gun, shooting it won't really hurt the value. And what the heck, you can't enjoy it after you are dead and buried.
It's a beautiful rifle. And the pictures look awesome! Well done!!!