Walk with Me - S3-E3
Revealing mistake: Merle is sitting in a chair and talking with Michonne and Andrea. At one point he takes off the prosthetic on his right arm to show them what used to be his hand (it's only a nub now), but shortly afterwards you can see his right hand in a fist as he puts the prosthetic back on. (00:13:00)
Answer: No, she actually tries to talk Rick out of it, but he's already made up his mind, minutes later when Daryl asks him about the location of his brother Lori says "he'll show you."