He had an "A" styled sheath for sale with it, which is "standard". Only problem is: The Goof pictured it with a Model #25-5" sheath, which is "not" only not standard, but "unavailable" for the #23. He noted it in the bottom of his post.
Just to be correct for everyone: When ordering a Model #23, "Gamemaster" you can get the following:
1) Standard Model "A" sheath with a hone pocket and a "handle-wrapped" keeper strap.

2) A Model "A" sheath with "NHS" (no hone sheath), which will give you a smooth front sheath and a "diagonal" (over the hilt) keeper strap.

3) No "pouch-type" sheath of any type is available for this Randall knife.

4) Either of the first two sheaths can be ordered with a tan, black or waxed finished.
I hope this helps answer a completely sensible question, asked in response to a completely unsensisble "for sale" ad. Thanks, Perry!!
Best, Capt. Chris