What you have here???
I'll tell you what you have: one of the finest pistol designs in the WORLD made by the finest manufacturer of that design - EVER! That is a super-nice gun; you are lucky you have it!!!!
It looks great! No all of them came with lanyard rings (you lucked out again). A new recoil spring from Wolff is probably in order; the original is terribly old. Might want to replace them all. While you are the Wolf spring page, get extra magazine springs too since they wear out, or better still, its probably best to just replace the magazines with new ones altogther (originals are probably shot by now; why risk it?).
Also, like with any HP, you will want to avoid +p and especially +p+ 9mm ammunition: STANDARD PRESSURE AMMO ONLY!
Also looks like the model you got has the early internal extractor; these are impossible to find so be very very careful with that; I would not even try to take it out of the gun at all for risk of it breaking (its one piece). They were originally "tensioned" at the factory when new and hopefully that original tension setting still works; otherwise you have a huge (expensive) problem on your hands. With that internal extractor, you might want to keep the round-count down.
FOr more info, google the page by the late Stephen Camp; his page (if its still up) is an excellent resource in trying to keep these old guns working. Congrats on your purchase.