Do I need to grout fireplace tiles?

I am redoing my fireplaces in my 1935 Bungalow. I found a bunch of mismatched antique fireplace tile and came up with two layouts for the two fireplaces:

http://xiard.shutterfly.com/470 (shows the top part of fireplace #1, but the hearth is not the final version)
http://xiard.shutterfly.com/480 (this is the final hearth layout for fireplace #1)
http://xiard.shutterfly.com/502

I have a guy who is installing the tile for me, and he's suggesting that I not use any grout at all. He's worried about what grout color to choose because of my mixture of dark and light tiles. He says he thinks that putting in any grout will spoil the effect of the antique tiles. He says he wants to just butt the tiles up against each other and not grout.

Certainly in fireplaces I've looked at from that era the grout lines are very small, and I like that look. But are they really ever laid without any grout at all? I'm also worried that he suggested this after laying the first hearth:

http://xiard.shutterfly.com/509

...and I'm worried that the spacing of the tiles in that hearth allowed for grout, and that I won't be happy if I don't put any grout at all in there. My gut tells me that not grouting is a shortcut rather than a design decision, but I'm a novice so I'm not sure.

Any thoughts?

Thanks,

David