1989 Cavalier Z24 ignition cylinder removal
 

Hi all, first time posting! I did a quick search but couldn't find anything about my issue. Please see below.

My fiance got a 1989 Cavalier Z24 convertible for her 16th birthday. It has only been summer driven and has about 120k on the odometer. The car was unfortunately stolen many years ago and the ignition and key locks were all popped/damaged. We had it all repaired and as time went by we drove it less and less as it needed a new convertible top and motor. Eventually it was put into climate controlled storage and has stayed there for the past 10 years or so. The building it has been stored in has unfortunately sold and we need to get the vehicle out. The problem is, we can not find the keys for the life of us, and since the ignition was replaced we can't get a replacement key cut through GM. I spoke with a local GM dealership who said if I can remove the ignition cylinder they can get the code off it and have new keys cut, so I started dismantling things. I removed the steering wheel, bought a steering wheel puller to remove the hub, but now I'm stuck as there is a metal plate behind the hub that I can not for the life of me figure out how to remove (photos attached). Does anyone have experience removing/replacing an ignition cylinder on these cars (or similar models)? Any help would be greatly appreciated. I had one mechanic tell me to remove the ring around the centre steering bolt so I purchased retaining ring pliers but I don't think that ring comes out (I've tried everything). I had another mechanic tell me to go through the panel below the steering column but that doesn't even open up anything near the ignition so I can't imagine that is correct either. I found a walk-through on a regular Cavalier (non-Z24) in the same age range but this metal plate doesn't exist behind the steering wheel hub in that tutorial. Please help!!! Photo linked below.

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