1939 Nickel Reverse(S) Question

It's something to do with the steps on Monticello. Either they were wavy or straight(?)

I'm not sure if this will help, but I have one of those coin prices magazines, and it lists:

1939 TI, wavy steps, Rev. of 1939
1939 TII, even steps, Rev. of 1940
Then the same as above for 1939 D and 1939 S
It also has 1939 Doubled Monticello TII

So maybe it means that some 1939 nickels have wavy steps, while some have even steps, like in 1940.
But, as xshift said, it would have to be nearly unc. to tell.

Breen's encyclopedia says that the reverse of '39 is "top step thin" meaning the top step is thin and the lower steps are thicker, and the reverse of '40 is "top step heavy" meaning the top step is thicker than the lower steps. He doesn't say anything about "wavy" steps.

Thanks, desertgem. Apparently it's all about the steps.. maybe under magnification I can get a better look at these. I'm doubting it though, as they may be just toooooo circulated. Thanks for the information, it's definitely good to know!