FWIW,
Talk about "buy now" on Lymans and parting things out AND piecing things together:
Right now there is a scope on ebay:
#261371075381
Listed as a 15X Targetspot.
Sure enough, I can decipher in one of the pics that it IS a Targetspot.   BUT, they only came in up to 10X.
Something fishy...
Sure enough, another look and someone had replaced the objective assembly with a SuperTarget Spot Objective.   
Nevertheless, if you want an external adj Lyman scope
for a "using" rather than collectables price, the $455
is probably ok for this "assembly"
beltfed/arnie

Mike,
I have to say, first of all that I am not Certain
what happens when a STS Objective is installed on 
a 10X Targetspot.
But, I expect the power was increased. Anyways, 
I still think that the Buy Now price of $455 is probably 
a deal for the scope as a shooter, whether its actually a 15X or a 10X or somewheres in between.
Also, we don't know from the description or from the 
poor pictures whether someone replaced the ocular/eyepiece with a 15X.  Who knows maybe it was a Lyman factory upgrade.  It is also noted that the mounts are of the old style with pointed clamp screws rather than the later cup shaped clamp screws. They work, but better you have early bases (for pointed on one side and for cup on the other) such as on my R2 Hiwall, or you can carefully, with a mototool, grind holes in the right spots for the pointed mount screws
beltfed/arnie