Forgot to add you should call Canada Customs and have them confirm the VIN is ok before buying as well.
A run down on what RIV says in regards to trailers:
Vehicle admissibility
My trailer did not need to be registered in the U.S., why does it have to be inspected in Canada?
Trailers are a prescribed class of vehicle under the Motor Vehicle Safety Act and require an RIV Inspection.
Registration requirements in the U.S. are not equivalent to
registration requirements in each individual Canadian province or territory. All trailers less than fifteen years old, including: utility trailers, enclosed cargo trailers, low-chassis trailers, air braked trailers, travel trailers, fifth wheel trailers, horse/stock trailers, boat trailers, car dollies, portable air compressors, log splitters, wood chippers etc. are regulated by the RIV program.
Are trailers required to enter the RIV program?
Trailers are a prescribed class of vehicle under the Motor Vehicle Safety Act and require an RIV Inspection.
All trailers less than fifteen years old, including: utility trailers, enclosed cargo trailers, low-chassis trailers, air braked trailers, travel trailers, fifth wheel trailers, horse/stock trailers, boat trailers, car dollies, portable air compressors, log splitters, wood chippers etc. are regulated by the RIV program, require an RIV inspection and are subject to the RIV import fee of $195 + tax.
What do I need to do before attempting to permanently import my trailer into Canada?
Prior to purchasing and permanently importing your trailer into Canada, we strongly recommend the potential importer to contact our office in order to ensure the validity of the vehicle identification number (VIN). For any trailer to be compatible for import into Canada, it must first meet four basic requirements:
1) It must bear a legible, valid, 17-digit VIN that has been issued by the original equipment manufacturer (OEM).
2) It must bear a legible U.S. Statement of Compliance (SOC) label, issued by the OEM.
3) It must bear a label, legibly indicating the vehicle's
weight ratings (both GVWR and GAWR).
4) It must bear a label, legibly indicating the recommended tire pressures (PSI).
Note: Trailers with a GVWR of 4536kg or more, manufactured after September 1, 2007, must be listed as admissible under Section 11 of the Vehicle Import Compatibility List.
If any of these 4 basic requirements cannot be met, i.e., something is missing or illegible, the trailer will be considered incompatible with Canadian Motor Vehicle Safety Standards (CMVSS) and therefore inadmissible for import into Canada.
General
The VIN on my vehicle matches the current registration, title certificate and bill of sale. Why is RIV saying it is invalid?
All admissible vehicles, including all types of trailers, must bear a 17 character alphanumeric sequence, as required by Canadian Motor Vehicle Safety Standard (CMVSS) 115 – Vehicle Identification Number.
Although the VIN of your vehicle may match all official U.S. documents, and although the trailer manufacturer may have confirmed that the VIN on the vehicle itself is indeed the assigned VIN, this does not mean that the VIN issued complies with U.S. and Canadian federal requirements.
The VIN is composed of the following sections as prescribed by the regulations defined by SAE:
World Manufacturer Identifier (WMI)
Vehicle attributes / model
Check Digit
Model Year
Plant Code
Sequential Number
Prior to purchasing and permanently importing a trailer into Canada, we strongly recommend the potential importer to contact our office in order to ensure the validity of the vehicle identification number (VIN).