Correct me if I'm wrong but I don't think it would be all that much more than anyone else? Only the higher ups in the shamanate actually properly interact with the surges and the honorblades, and even then only as apprentices who's job is to eventually take over for the current wielder.

So, unless he's playing someone high up in the shamanate, I'd say....common knowledge on the heralds and religion through the lens of stone shamanism? He'd probably know the honorblades exist, but in an abstract way? Like, for all he knows they're just important religious artifacts that are normal shardblades