Can you explain what kind of weapon it was? Do you have the specification? Yes it can be help by CBSA. It happened to me in 2006 for a Tokyo Marui Famas and yes they kept the AEG...
But to be a replica, the weapon needs to be real, means that if that does not exist in real, you can argument with CBSA. Also, if the Weapon was not shooting, you can also argument that it cannot be use.
I suggest that you read carefully first
https://www.cbsa-asfc.gc.ca/publicat...-13-2-eng.html
And than contact CBSA with your tracking number.
Good luck!