Thundercat part help

Hi

Does anyone have an idea of what the part is called that fits in
the end of the swingarm and where I can get a pair?. It's where the locking nuts are for when you're adjusting the chain. I'd describe them as a rectangle piece of metal. The reason I'm asking as mine are currently gaffer taped over and yet to take the tape off, got a feeling they may be missing or heavily corroded and the last owner put the tape over as a bit of protection.

Any info appreciated.