BobinNH: I would like to know the answer to your question as well.
I have two mint condition pre-64 Model 70 Standard Rifles in caliber 243 Winchester. And as I turn 70 next year I am going to start selling down my collection "at a convenient time" instead of leaving that task to uninformed heirs.
I ignore gunbroker for the very most part as scams thereon, anymore, are 10 times more prevalent than in person or at gunshows - so I really can not answer your question directly. And my 243's have been in my collection for so long I have forgotten what I paid for them.
I have always liked the pre-64 Model 70 243's and have 11 of them total, including Targets, Varmints and Featherweights along with the Standards.
I have not seen an original, collector quality, 243 Standard Rifle at a gunshop/gunshow/gunsale in a LONG, LONG time!
Long live the Riflemans Rifles!
Hold into the wind
VarmintGuy