That's a good price if it's in good shape.
There was a CHP variation of the pre-rail 4013TSW. Does that one have any asset numbers on the other side?
Mine below has a MSF52xx SN# & you can see the CHP inventory asset #s on the frame, slide, & barrel.
The CHP model is the same as a standard production 4013TSW except they don't have the trigger play spring installed, which is no biggie.
.
.
.
And Yes, only the 4013, non TSW, can be converted to 10mm.
The TSW mags aren't long enough for a 10AUTO cartridge & their barrels & frame aren't as beefy.
Otherwise they're perfectly fine pistols, I have two.
.
.
.
.