The grenade is a post war Korean War grenade and not appropriate for WW2. You could change the head and a the spoon and still use the body though. Here is a more appropriate looking one for your display:
the fuses run about $15 and the grenades $30 which may be a bit pricy. However, they are WWII correct in appearance. you even get a choice between M10A1 and M10A2 fuses.
Using some bodies i had, I made up an early MKII with a M10A1 fuse and a few MKIIs with M10A2 fuses. My efforts are pictured here.
_ If you have some post-war bodies and decide to buy the fuzes separately as the First Sergeant stated, the threads on the fuses are to small (1/2-13). My solution was to mill off the threads, tap a 1/4-20 hole through the fuse (there is a through hole in the body perfect for a 1/4-20) and bolt on a portion of 5/8-11 all-thread. this worked great. My modified fuse is shown below.