The short answer is that YES the wcr-gn-r will dole out ip addresses both wirelessly and to wired clients when it is set as a secondary router wirelessly bridged to another primary router (which is acting as the sole dhcp server for the entire network). I have three routers running one network in the house.
Router 1 is a d-link model DIR-655. Router 2 is an old Linksys WRT54G with firmware updated by DD-WRT. Router 3 is now the Buffalo wcr-gn-r. Router 2 can only communicate at 'G' speeds. While Router 3 is connected at 'N' speed. Sadly due to wireless overhead, there is no improvement over he old Linksys. I surmised this would be the case but it is nice to confirm it.
So anyone else out there thinking that going to the trouble and expense of installing a newer Router will improve the throughput - take it from me don't bother. Buy an old blue linksys from craigslist or ebay or somewhere like that. Toss on DD-WRT and that should do nicely.
How To Configure Buffalo Router As Repeater?