That absolutely does get a reaction out of him. It's just that his reaction is staring at the Sith very hard and with a decided air of shock and then disbelief.

Not by what he's claimed to have done, but the sheer amount of time that had elapsed.

"As near as I can recall from my history, you have been buried for three thousand years." That is a long, long, time by any standard. It takes him a second to recover and go on: " I'm offering you assistance because I have no desire to have you in my backyard, and it isn't as though one more Sith in the galaxy makes any great difference."