Restrict User Access

Can Conditional Field Level Security (CFLS) be used to restrict user access to a limited number of items (i.e., Production Manager can only see / create assembly entry of the item he/she is producing, not of all items)?

CFLS can do what you are asking so long as you know where in GP, all of the places where ‘item’ would be visible in order to put the record level security conditions on all of those places.