Nope, not on the people sending in reply cards. More than half the people I see are getting extra help for their part D and/or Part B premium.
If you specialize in FE you will not find many SPWL buyers in that market. It's rare to even find med sup buyers. I do over 300 FE apps per year. I only do about 20 med sup apps per year. Half of those are from referral from my FE clients instead of them being able to buy themselves.
It's also going to comeback to what demographic you are mailing.If mailing higher incomes you might find more buyers. The returns go down because most people that can do SPWL or preneed policies have an agent. The typical FE reply person does not have an agent.
That goes back to what travis said, "if you chase two rabbits you will lose them both".
You can still find them if you look for them. Like I said, most agents don't know how to look for them.
You said yourself that some of the people mailing back are looking to add to what they have. That's a place to start looking; those with paid up policies. Another place is for those that have CD's set aside.
They are out there, but you'll only find them if you are looking.