Some very interesting information in this thread!
I purchased my shorty 9 from a friend years ago but it didn't come with the box or docs.

A few things from memory, there was a thread a few years ago that outlined precautions on the proper procedure of removing and installing the slides with the Briley barrel bushing, apparently if done wrong or carelessly it can damage the barrel and bushing and good luck having that repaired as each slide/barrel assembly is hand lapped n fit to each frame and serial numbered to that frame.

The two magazines that came with the PC9 are interchangeable with the 5906 series but they had the PC emblem on the slide body, ( my PC shorty 40 magazines are also PC marked).
On a side note those blue plastic PC boxes have been out of production for some time now but SW had a newer style grey PC plastic case you could buy for around $20 a couple years ago new as a replacement,
while they aren't period correct they are a better box than the original and are a factory SW product and PC marked.
I didn't realize there were two different serial prefix, will have to dig mine out and check its serial, IIRC it is PCV like the Op's.