I know bone grafts/augmentations are necessary for many cases of dental implants being applied, but is it the same case for dentures too?

Not Necessarily. Each patient is slightly different. Obviously bone grafting can help preserve the ridge... a good ridge will help support a denture.
Bone grafts. There are procedures to try to build up bone before the placement of dentures. However, they are seldom done and prognosis is questionable. That is why it is so important to try to preserve bone and teeth and not require dentures in the first place. The best way to get a good fitting and functioning denture is to be in the hands of a very competent restorative dentist.
No. In fact, it is not very successful to try augmentation/grafts if dentures are to be worn. The dentures will simple cause resorption of the new bone/graft as it does with the existing bone -- but usually at a more accelerated pace. We tried much of this in the 80's with little success. At your age implants are the best long -term solution. See a Prosthodontist - expert in implants/dentures. G.Luck.