Ok, I will opine. I think SBTs, in general, are becoming less desirable. With the popularity of Sporting Clays surging, and Trap waning, or at least stagnating, those who want to shoot more than just ONE category of all the current shooting sports(Trap, Skeet, 5Stand, SC and bunker) will not want a SBT that can only be used for Trap. I have several SBTs that get limited use now. Like them a lot, but wish I had a nice O/U instead.
I have an unaltered KS-5 Special that I have owned for over 15 years. I think I paid $3600 for it new at Jaquas. I really like the gun but may be a tad light when shooting 1 1/8 loads. I do not have a doubles gun. I have considered a K-80 but yikes when I look at the price tag.