It's kind of difficult to verify NOS Sideart/CPO with DK because there are such good and accurate repros. Having said that, I'd go with "verified" NOS everytime. I've not had an issue with the adhesive from an NOS - yet. Fingers crossed.
The 150.00 does seem high for that set. I would think 100.00 - 120.00 tops, would be what I'd fork over.
I have a spare verified NOS DK Instruction Sticker laying around. Let me know - if you're that hardcore about NOS, otherwise the repro instr. sticker is just as good and would be cheaper.
When verifying the NOS CPO, if it has a Instruction Card in it. The last couple lines should be "red" lettering, not "white". Most repros have the white.