Both my 3540A drives are (one actually "was" - it has failed..) made in Malaysia, May 2005. The first one was silver, the second one is black.
Both are excellent writers... no complaint about writing quality. My Pioneer 109 still has an edge for some media, but it's slight.
Actually are there many retail versions of the 3540A? I'm asking because in my experience, there are more variations between bulk electro-mechanical devices than between retail ones. I've always thought that the reason for this was the transport, bulk appliances being more prone to shocks because they're often not conditioned very carefully. And then, there is handling in the shops, where retail appliances are better protected against rough handling than bulk ones are...
I'm not saying this is the reason behind the variations between 3540A drives, it was just to throw in my 2 cents.