Fun with part numbers

I’m now getting to the bottom of the pile of burnt and buried glider parts and its getting more difficult to identify and catelogue the parts from the incomplete APs at my disposal. So looking for the part numbers is getting more important. Until that is I came to these three identical (or at least I thought they were) swinging arms.
[ATTACH]187411[/ATTACH]
Only after laying them out for this photo did I notice that one arm is slightly longer even though the working length is the same.
[ATTACH]187412[/ATTACH]
So its hunt the part number time and what do I find? not one number is the same!
I have part number combinations of 212 CR / 155 3CR, 33 30AR / 8129CR and ?? 4BR / 9 5CR (the ? are now just pits of corrosion). The only thing in common is the CR, I wonder what it refers to? (I’ve checked the list on this forum and its not there)
[ATTACH]187413[/ATTACH][ATTACH]187414[/ATTACH][ATTACH]187415[/ATTACH][ATTACH]187416[/ATTACH]

So guys any ideas? From the APs I know what they aren’t and as the rest of the stuff is Horsa and Hamilcar, I can only assume they are as well. Its most frustrating