HT Games
If you're searching for the iconic RPG-7 in Metal Gear Solid: Portable Ops, you won't find it. The rocket launcher simply does not appear in the PSP title. The game features the M47 and the Stinger missile launcher, but the classic RPG-7 is absent.
You are likely thinking of Metal Gear Solid 3: Snake Eater. In that game, the RPG-7 is a usable weapon found in specific locations, such as the armory inside Groznyj Grad or carried by enemy soldiers during certain alert phases.
Portable Ops focuses on a different set of heavy weapons. The M47 serves as the primary unguided rocket launcher, while the Stinger provides lock-on anti-air capability. If you're playing on PSP and need explosive power, these are your go-to options.