Yep, just got one. From a First Communion party, thanking me for my gift and my presence. Not even signatures, just pre-printed. Envelope was handwritten, though.
Pretty sure by that age, I had to at least sign my own thank you notes. We gave $150, I think.
ETA: what kinda gets me more than anything...if you did pre-printed, why did it take a month and a half for it to go out?