Great Price
I think the site difference is that the Sig Night Sites are *2 dot, white/glow-green (green in the dark, white for day use) that will glow 24/7 for aprox 8 - 10yrs.. vs standard shooting sites, no glow IIRC.
700 bucks for a NIB P220R Two-Tone, SAO, is a great price and, having a P220R DA/SA, myself, for about a year now with just over 1000 perfect rounds down-range, I wish I had an SAO trigger, (knowing what I know now in that particular Sig model) locked and cocked, Sig, like what you may get, IMO, the best of all worlds, including price..
*got these sites with my P220.. very good sites.
Let us know what ya get,
Ls
Ps.. welcome to the THR forums..