Here are some pictures to help you determine if your current carseat has 1 canopy bar or 2.
To see, scrunch up your canopy so you can see the bar (s). A 1 canopy bar is pictured below. There will be 1 adjusting bar as well as a fitted back or elastic back that fits securely around the back of your carseat.
A 2 canopy bar cover is pictured below. There will be 2 adjusting bars, one in front and 1 in the back. This allows the cover to fully extend to the front of the carseat as pictured below.