I have several of these and noticed the "Cordell" and the "Big-O" words on the sides are done 3 different ways. I assume they are different ages. One type is cursive and the other 2 types are not. Any info on these?

If it is the plastic version then you have a decent crank, but it can't touch the legendary status of the original Fred Young wooden version these plastic baits were based on. There are some really crazy paintjobs on some of the older plastic cordell big-os.

Cordell reproduced some wooden FY Big-Os a few years back. They mostly ended up in the Bargain Cave at Cabellas and are easy to find on Ebay. Some of the paintjobs are very nice, but I don't do so well on that crank.

They are plastic. Any idea how to tell how old they are (based on the style of the words on them maybe)?

Not sure. Cordell started selling the plastic Big Os in 1973 and still sells them. I looked for a little bit on google trying to find a chart or way to ID them, couldn't find much, but I only went three pages deep...