Lower.
There are many elements of truth in what Jody V says. But you must remember that the overall fact is that the gun is a prohibited class unit. Run-of-the-mill prohibs do not attact high prices unless [and this is the exception] they have a factory desireability that makes them stand out from all the other prohibs.
12[6] Pythons, Diamondbacks, Anacondas some S&W's, some exceptional Lugers, will be worth more, but only to someone willing to bite on the price.
So, as for your Colt, while it is a very nice revolver and does have some extra value over some prohibs, most of the prices that I have seen quoted before me are way too high. Without seeing it, a nice 4" Colt KC is worth C$250.00-C$300.00. Some, including me might go a little higher to say C$325.00-C$350.00 but that's about it.
Should you command and get a higher price, good for you, but don't hold your breath....