176.00 apiece? GIVIN' em away!
Not really. The P320 design is so brilliant from a "value engineering" perspective that they could probably sell them at $150 and make money. I remember the first time I took apart my P320 FCG. (do not recommend if you are impatient or uncoordinated). Most all the parts are MIM, laser cut, or stamped on the inside. This makes for easy fast production, meaning cheap.
Now consider that every variant of the pistol can use the same exact chassis. You can amortize that cost over several hundred thousand units. Then you have the plastic grip modules which are the same for each size (except the .45 versions which can be made int he same molds with an insert change).
The most expensive parts of the gun are the barrel and slide. So there's only so cheap they can make it. That's why they can't sell them for $80 and make money. But I'm guessing Sig has about $30 in each barrel, $40 per slide, and maybe $30 for the whole rest of the gun-- roughly $100 actual cost per gun.
The only reason Sig prices them at $600 is because that's what plastic striker guns from reputable brands generally go for, and they add a small premium because they are Sig and can point to their metal gun marketing as a "premium" product.
Truth is, they probably don't cost much more to make than a Hi Point.