You are talking about 2 different things in 2 replies.
First one is Operation with PM02. 2nd one is Component Reservation.
You can have Operation with PM02 (External Operation) & Component with Stock Item (L). So, PR will be generated for Operation & Reservation will be generated for Component.
Not clear on your query. Provide the Business scenario instead of speaking in SAP terms. Let us give you a solution in SAP & then check whether it suits your requirement or not.