To me that looks like some of those spanish made decorators, they have sometimes nice looking carriages but the barrels seem to be always very thin-walled and strange looking, look down the bore shows a completely hollow and very rough interior.
They also have most of the time some small brass plaque nailed on the carriage which has the "model" of the cannon and some other info on it. The model in question also has this plaque. If it is really one of those spanish decorators, the price estimate of $450-650 is unbelievable... I think I paid $10 for the one spanish decorator I have.