Yeah, those motherboards are solid: usually ABIT or ASUS, I've ordered and used about 10 of them and have never had a problem. They have all been new also, guess they built a crap load and then never sold them.
edit: just reread your message, you said your brother already has a 423cpu, just needs the mobo, and you'd rather give him one that you know works (yours) right? And you have a 423 cpu and you want to upgrade your mobo and want to keep your cpu? Am I getting all this correct?
My advice: give your mobo and cpu to your brother, tell him to sell his (those 423 cpu's really sell for a lot), then upgrade yourself to something faster than you could ever go with a 423-willamette-cpu.