Wow. Tough question to answer. Based on serial numbers I've seen at the local gun shops, and the fact that production s/n's had a prefix of PR2005, and actually began at PR20051, it looks to me like the number must be in the hundreds, and not in the thousands. I've seen one that had a PR20053xx, which would put it in the 300's zone.

If anyone out there has seen a higher number, please post it. Thanks.
Hope this helps,
...Deeton