DESIGN CHANGE NOTES
Penn has notes on their schematics about shaft with pin design and shaft with washer design. It looks like they started out making the reels with the pin shaft design, then partway through the first production run, they redesigned the shaft to the newer washer design. The schematics reflect that change.
The spools currently available contain the newer 117- drive plate which fits either shaft design, so they are compatible with both.