No. When you enter an IP address in the Chooser, you are using AppleTalk over IP (AppleTalk encapsulated in IP packets). When you just pick AppleShare Client in the Chooser, you are using raw AppleTalk (EtherTalk to be exact) packets over your ethernet interface. Some vendors don't pass the raw AppleTalk packets over the wireless interface. Linksys is well known for this. I don't know if Apple dumped AppleTalk support in the new Extreme base stations, though...
Peace,
Drew