The RCMP "opinion" on many parts of the law is suspect. So much so that they go to some lengths to stop some of them being tested in court. Examples include 10/22 magazines, antiques that have been converted to different cartridges and the 1500 guns who's FRT entries have been changed to prohibited since last May's OIC.
There used to be in the stickies above, a template for an antique status letter that cited the relevant laws and had places to include the make, model and FRT numbers for your particular gun. I'm aware of people having used such a letter to import from the US and as an aid in speaking with LEO or conservation officers to good effect.
To get the RCMP letter they apparently require you to register the revolver and will afterwards or as a later part of the process see if is eligible for antique status. Many people are unwilling to go through the hassle and the likelihood of its being documented to get a note from them saying what is already possible to determine from other sources such as armalytics.ca, a Colt letter, proof marks, serial number records etc.