Hi! I'm late to the conversation, but I've always wondered about the pronunciation of our last name, too. My family has always rhymed it with "wild." Sometimes, if I'm talking to someone I'll probably never see again who just needs to look up my name, I'll pronounce it like "build" to avoid confusion. My first boyfriend misheard my name and thought it was "Giles" for six months-- and this was AFTER he'd been listening to my dad's radio show for years and had ample time to familiarize himself with the name.
I've never heard of the convention of a silent D, but it makes sense. That final consonant, as my ex demonstrated, can be hard to hear. One of my high school history teachers theorized that the pronunciation sounded Dutch. But the Guild family tree is mostly Scottish, right? I don't know where Dutch would come in.
Sometimes it seems like it would be easier to switch to the more straightforward pronunciation, but it just doesn't feel right. I'll deal with occasional confusion if it means I get to keep the name I grew up with. It makes me happy to read that so many other people pronounce my name the way I do!