Re-using stream or Baseline in GCM

When you create a new stream from another Stream/Baseline in GCM (or even local configuration), the content of original stream is replicated in the new stream.

From usability point of view, these are requirements from original stream that are re-used in the new stream. If you notice, the ID of the requirement will be the same. So multiple versions of requiements are held in different streams/baselines.

So if you're looking for a count, from sizing perspective (monitoring resource usage), then yes, the count will be 1000. Here we use the term versions instead of requirements.

It depends on what you mean by "re-use in GCM".   If you mean you are adding that stream/baseline to a new global stream, then nothing is copied ... you simply re-use the same artifact versions in both the original and in the new global stream/baseline (so still 500 versions).   If you are creating a new global stream by branching from an existing global baseline, then again, no new artifacts are created ... you just get a new global stream that has the same contributions as the baseline you are branching (again, still 500 versions).