No they are most likely ACID clips. They should follow the tempo and pitch.
If they have rounded corners they are groove clips meaning they have been acidized and can be "rolled" out on the track. The one caveat is the clip needs to line up with the measure. Otherwise it could go out of time.
From the help file
How Groove Clips work in SONAR Groove clips have information saved within them which allow them to adjust to changes in tempo and pitch. Groove clips can read a project’s tempo and tempo changes, and can adjust their root note pitch when they read pitch markers. You can add pitch markers in the Track view’s Time Ruler to transpose the Groove clip. As your project passes over a pitch marker, SONAR transposes your Groove clips based on the clip’s root note reference pitch. If you insert no pitch markers in your project, there are no pitch changes in your Groove clips. The default project pitch is C.
Note 1: When working with Groove clips, it is important to know the difference between key and pitch. Your project’s key signature has no effect on Groove clips. The pitch of your Follow Project Pitch-enabled Groove clips is dictated by pitch markers in the Time Ruler. If there are no pitch markers in your project, these Groove clips play at the pitch set in Project > Set Default Groove Clip Pitch (the default is C).
Note 2: Groove clips must be at least one beat in length. If you try to loop-enable a clip of a shorter duration you may experience distortion or artifacts
Sonar can work with REX files too, but not in the same way.