OK I GOT IT ....lol
You mean a lip on the inside of spool where the Line goes .
One with the lump is older than the one without it . Thanks for explaining this .

Ok so My Squibber with the Off -On- Gear  notations, and No Numbers, Plastic Edged Spool with the Blender Blades inside on Clicker Side and a Notched Lever tab is 1946 eh?

 Yes grasshoppa, 1946

 Using Penn catalogs to date a reel is very helpful, but don't go by the illustrations in the catalogs. Penn used same illustrations for many years of catalogs, despite some cosmetic changes that should've been illustrated, especially the changes in handle arms and knobs and counterbalance.

 So, back to my point. Starting in 1950 Penn reels now had visible stamped part numbers on most every part. So if your reel has part numbers, you know it's 1950 or newer. The slotted rod clamp phased out in 1954 is another telltale sign. Another is type of spool, and also type of knob and blade, and yet another is for senators with bushings and when those switched to ball bearings.

 So, here we see a numbered 9/0 with slotted clamp, bushings, counterbalance handle, and 3 piece spool. Easy to say this one is 1950-53

I ended up with this Reel and here are some HOPEFULLY AGE IDENTIFYING pix for Mr Max to elaborate on 
The Spool is Plastic NOT ALUMINUM and has looks like a Blender option on the clicker side .

              The clicker side of Spool


The Edge of Spool  looks like a small raised edge on it



And the Knob  (Odd Color ,almost See thru or opaque

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