Newby Arty questions

[OMCHamlin]

I lucked into a pretty good deal on a 1917 DWM Artillery Luger with matching holster in about 90-95% condition and want to know a few things about it.
1. Is it ok to just go ahead and shoot this thing? (I should say continue to shoot it , I already have and it is wicked accurate, as long as I keep calm on that 15Lb trigger!)
2. Should I replace the springs as a matter of "preventative maintenance"? (keeping the old ones, of course!)
3. Ditto the grips, as they are clean and un blemished.
4. It has a non-fluted firing pin, should I replace that as well?
5. It is all matching, except for the sideplate (anyone have a number 13?) and is "in the white" on the inside, so I assume that means it has not been refinished?
6. The toggle seems to be very easy to pop up when the gun is cocked, but not so after firing, is this normal, or a sign of a weak spring?
7. Anyone know where I could find a couple of correct spare magazines (that function well) for it?
8. Ditto a genuine board stock for it? (I picked up a repro from Gun Parts Corp and it's a real "P.O.S", loose, poorly inletted and not worthy of the gun by any means.
9. Lastly, I gave $550 for it, was that a GOOD deal or just a good deal?
Thanks in advance,
Chris