i just had my MBP screen replaced as well. the mac idiot asked me if i knew there was only 256mb installed when i brought it in.

of course i do. his words were, "we are a little confused why there is only 256 in it, did u know this?"

i then said yes, and told him to fix the screen. There was tons of dust in it, i mean tons. He looked at it, and got rude with my girlfriend saying, "i dont know if its getting anything done to it yet."

man, the appointment started out nice, but went straight downhill.
back to topic, and moral of my story,

3rd party ram is fine if they act like they know more than you and wonder why, tell them to get on their site, and just do their job