Sorry, I don't have a revolver that formerly belonged to the BCP. But, you've answered a question that I've been trying to pin down for 2 years.
I bought a Winchester 1897 riot gun with BCP markings 2 years ago. The seller assured me that the gun was part of the BCP armory until they were absorbed into the RCMP. The provenance on this gun is that it was "liberated" by a member when it was slated to be chopped up. At the time of sale, the vendor told me that he personally knew the BCP member who sidetracked the gun. But, for obvious reasons, these details would never be confirmed.
I've often wondered if the BCP story was true. The fact that the gun has the proper steel butt plate for a riot model, but also has a chopped, full choke barrel (which never came on a riot gun) always made me wonder.
Thanks to your post, I now know that British Columbia Provincial Police property actually was marked simply "BCP". And, that what I have is, at the least, a fake made by someone who was familiar with BCP procedures. More likely, though, it really is a riot gun from the BCP era that just happens to have a replacement barrel.
Sure glad I saw your post. I wish I could help you in return.