Ok, I looked at the letter and it is on their letterhead and I actually spoke to the person who signed the letter (not a copied signature). The enclosed paperwork and instructions are all on their papers. I actually called the number twice and spoke to another person who verified everything on the paperwork they sent. They also have a return envelope to put the paperwork in going to their company and on the envelope is written in red 'death claims'. I'm pretty sure it's legit. There are many insurance companies listed on the claimant form that are under them.
Here's what the letter said (2 paragraphs):
"We would like to fulfill our obligation under insurance policies that were never claimed at the time of Ms. XXXXX death. Since you were named beneficiary on these policies, we ask that you complete the enclosed Claimant's Statement and return it to us along with a copy of the insured's death certificate. A return envelope is provided for your reply.
If we don not hear from you, we will be required to treat the policy proceeds as unclaimed funds, making them subject to payment to the state as an abandoned property".
What do you all think?

Maybe I'll make one more call on Monday.