Trade deals are negotiated through the executive branch.
For example, the Candians are trying to put transgender issues into the USMCA trade deal.
They are usually all or nothing to be accepted by the Senate or not.
The house has little say on trade deals.
Changing Canada’s gun laws is not a trade deal, it is a legislative function.
I suppose Trump could ask Trudeau to push an initiative through Canada’s Parliament, but given their current atmosphere of wanting to enact even stricter gun control laws, I wouldn’t hold much hope.
The old system of declaring firearms at the border and again when leaving Canada seemed to work just fine, and there are a lot of people who move to and from Alaska every year that would like to move their household goods through Canada.
I’m not sure why Canada felt the need to change that law in 2001.