I wouldn't say all the time. You'll occasionally see a Delta 757 at LGA now for a sports charter, otherwise it's a one-off situation. It's been since Covid that LGA is an A32x/737 station.

Not out of the norm to see an Air Canada 767 at LGA - they'll often bring them in around the holidays and if there's a big disruption in YYZ, they'll bring them in to try and clear some extra passengers out. Gate 51 at LGA in Terminal B is equipped for widebodies (49 needs to be shut if so).

This shows 757/737 gates at LGA; very easy that they could shut a gate next to one of these to handle a 767.

lgasetup_b98ddc914b3bac4249baa6dce039724960864264. jpeg (1710×1258) (ibsrv.net)