Yes—if you have a stereo image pair, you can estimate scene depth and generate a depth map. That depth information can then be used to apply distance-based blur in post-processing, which can simulate shallow depth of field and potentially a tilted focal plane similar to a tilt-shift look.

The catch is practicality: there is no simple, automatic method that reliably produces a perfect depth map from stereo images. This is a known computer-vision problem with lots of academic work behind it, but it is not generally a quick one-click workflow. Likewise, convincingly simulating optical blur from a depth map is also nontrivial, though tools such as Photoshop’s Lens Blur can get reasonably close.

So in principle, yes: stereo 3D images give you the information needed for this kind of effect. In practice, the process is complex, and using an actual tilt-shift lens is usually much easier if you want a true optical result.