How to Date Old Track packages

[Rail Co]

Hey guys, I have seen about 3-4 different types of packaging for the old blue 4.5v rails and I am wondering If I can date them easily by the box style without opening it

This is my sealed box:

Lego 155 MISB with plastic shrink warp fully intact. by Railco1, on Flickr

Lego 155 MISB with plastic shrink warp fully intact. by Railco1, on Flickr

I hope someone can help me date this without opening it accurately!

Thanks

-RailCo

P.S. Should I open it?

[Duq]

Send Gary Istok a pm; I'm not sure if he reads the train forum. He's an expert on old sets.

http://www.eurobricks.com/forum/index.php?showuser=1550