Most probably. The previous GTA games all had story modes, and it's expected that GTA 6 will continue this tradition to offer players an immersive narrative experience.
The GTA story mode has little to no effect on the online mode. They are designed to be standalone entities. Even though they share the same game universe, the mechanics and progress are separate.
To get GTA 5 online weapons in the story mode, look out for hidden packages or rewards during key story events. Sometimes, you might need to reach certain levels or achieve specific objectives to unlock them.
The Adder is a great car in GTA 5 story. It's very fast and has a sleek design, similar to real - life supercars. It can easily outrun most police cars during high - speed chases.