I have three of these spools. All marked 109d-501 but two have long gear side shafts and stepped down go code side. I'm guessing the two long shafts are for 506's??
Same spool "body" being used on two different reels, hence the different shaft setup, I think.
We've run into this on the 345 spools...same body was used to make the 113HLW spool but with different shaft setup.
However, my notes only show the 29L-501 stamped 109d-501
I don't have it noted which reel spool the other one is! Maybe someone else knows?