You are not going to get (or should not get) an upgrade on an award ticket.
Copa seems to be very stingy about awards and upgrades, so even if they have this WL then you are probably not got going to be lucky.
I recently had an M fare with a nearly empty F cabin at booking. It's eligible for instant upgrade like Y an B (and M for 1k) on UA. Didn't happen. Then the window for elites comes around starting at 4 days. Nothing happened. Not until the day of travel and the agent did it as a "special favor" at check-in. The flight went out with at least one non-rev and 2 empty seats of 12.
So if you have a revenue ticket then your chances (as silver) might be better on the day of travel. My experience was PTY-IAD.