The O1070 is actually an XSE number, but that's still too high for a used pistol.
http://www.coltsmfg.com/cmci/XSE.asp
I bought all three of my Colts* brand spanking new from Bud's, and none of them was much over $800 or so at the time.
In today's buying frenzy, they may have crept up a bit, but $900 is still too much for a used one.
*Lightweight Commander O4860XSE
Stainless Commander O4091U
Stainless Government O1091