The P-64 is a stout little gun. $379 seems high until you figure in shipping and FFL fees. The ones I see come with one mag, and Wolff springs come recommended on these guns. The sight work sounds interesting. All that stuff adds up. I like the 9x18's myself. Congrats.
Nice P-64, reminds me of mine without all the same holster wear. It was my first carry pistol, and even though 9x18 is hard to find locally I keep it ready just in case. I think mine came to roughly $300 when I bought it with 2 mags and a gigantic shoulder holster for what had to be like a .44 magnum or other long barreled revolver. So far it's been good to me, and my only complaint is the price of ammo since the only thing I tend to find is Sellier & Bollier brass. It actually prefers running steel cased ammo most of all.
If the P-64 is like my old IJ-70 .380 I had years ago(Russian Mak rebarreled for .380), you can buy the different springs to change the trigger pull. I had mine down to a 5lb DA pull and a paltry 1lb SA pull(with the usual Russian trigger slack before engagement). IIRC, there is a "fluff-n-buff" trick for the trigger as well.
Nice score. Silver Bear used to make a decent 95gr HP for those at one time. Haven't seen it lately.