Will be perfectly fine so long as 21-2N or 21-4N, a good 80% + heat is transmitted through the seat, the only thing that concerns me is why the seats have been "re-lapped", if you mean re cut, with a proper SERDI seat cutter machine that's fine, but they absolutely must NOT be lapped after cutting on a serdi, the serdi is actually that accurate lapping worsens the seal, some "old skool" people still aren't convinced that these machines can be that good!!
I'm not running sodium valves if that helps to re assure you.
tabetha