A.C.
I think EVERY baby is special and its arrival should be celebrated to the fullest degree! So yes, I think it's fine to have a shower for a 2nd baby.
I kept all of my baby items and had my children less than two years apart so for my second pregnancy my mother threw me a 'pamper the new mom' party where all the guests brought something they thought I would enjoy. It was really nice and much more low-key than a regular baby shower.
Just a thought!