I have a top lever but it's Meriden and doesn't have the engraving that a Aubrey would have (at least from what I've seen on the Numrich site). I've got some cocking rods that I'm going to try and modify for my 20ga unless I can find some original ones. Looking at Ebay there are quite a few parts listed for Meriden and Aubrey. I do have some other miscellaneous parts I could send you pics of if you like.
Kirk