Yes, the membership chairman of the chapter should receive the rec. You can access your university's greek life webpage and probably find the address. It will be listed with info pertaining to that sorority.
Note- this is the reason I always tell pnm's to include a
stamped envelope addressed to the chapter when they give a rec writer their resume and pic. It just helps the alum out and is a nice gesture. Also...don't forget your thank you note!