A magnet won't stick to non-ferrous materials. If you don't get stickage you can go ahead and get dollar signs in your eyes. An SR bottom bracket is expensive.
I have a bunch of shifters from this vintage...and maybe barring finish work there just isn't any difference that I can discern between SR and Record and Nuovo Record. I think that they shipped the same shifters with every group. (not nuovo grand sport...they had different mounting hardware).
I seem to be having problems with the shift key...HaPpY neWyEAR tO You, ONE AND ALL!