Mel-
Great idea for a birthday gift! This particular part number will not fit your husband's 2013 Toyota Tundra. Here are the part numbers that fit this truck.
This one fits the double cab http://jo.my/li0xe0
This one fits the crew cab http://jo.my/sdzah7
This is the mounting kit for both http://jo.my/6dkgx4
Westin does not currently offer a running board for the standard cab but if you want something similar for a standard cab Dee-Zee offers a black running board here http://jo.my/wb1pa0 and the mounting kit for them here http://jo.my/iq435g