Hi Bilal,
Yes. If you start the planning process from manual one, it will be taken care(Open orders). As said earlier, please set the MRP parameter properly (Masted data and customizing data-SPRO). Though you are doing the proposal manually, it is visible in MD04, MD06, MD46, MD47 etc. Hence planning is possible.
Still I will suggest to try it on sanbox for confidence.
Hope success and cheers 
.
Regards,
Krishnendu.