Daiwa BG20

[Himesrun]

I just picked up another old Daiwa BG20 off of an obscure online auction for 20 bucks. It was buried in a "grab bag" type lot of misc. fishing stuff and barely noticeable which is why nobody else bid on it. Anyway, it's in great shape with just a little surface ware and turns nice and smooth. In fact, the handle will spin 9 times before coming to a stop which is better than my newer BG's. I'm still going to tear it down and give it a deep clean anyway. My question, I was wondering if anybody knows roughly what year they changed from the ball type handle base to the flat style seen today? I have a few but non have this style handle. Just curious on the age of it. BG's, gold series, silver series......I'm a sucker for all of them and pick them up anytime I find a "deal".