I am considering selling one of my guns to fund another project. Just not sure what I should ask for it.

Springfield Armory XD 9mm 5" Tactical
Competition action job from the custom shop (4 pound trigger)
2 15 shot mags
Hard case
SA cable lock

Gun has had less than 500 rounds through it. The action job runs $195 from the custom shop. Is $600 a reasonable starting point? You can buy a new tactical for $500 locally, that includes the XD gear. But most shooters dislike the gear and don't use anyway. Am I in the right ballpark? Thanks for any input.