I think Penn switched over to that plastic plate in the late 1980s, and they discontinued the 706 for a few years right about then. When they came back, it was with the plastic. You'd probably have to look for a used one somewhere. The old green ones have aluminum plates, but it would be a shame to buy one and cannibalize it for that part alone---the plate would fit but your reel would look odd.
I never had a problem with the 4 Penns I have (two 704s and two 706s) that have the plastic side plate. Is yours getting exposed to excess heat?
I never had a problem with the 4 Penns I have (two 704s and two 706s) that have the plastic side plate. Is yours getting exposed to excess heat?