Penn 109D-501 spool - different shaft lengths

[JRD]

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??

[mizmo67]

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?