Can I export Address book from OS 10.7 to OS 10.5?

Thanks, and correction (yikes): I actually am working with 10.6 (not 10.5). I like the older Address Book format and would have retained it in 10.7 if I could have. Is there any risk in messing up the 10.6 Address Book program if I try to force on it the newer formatting of 10.7. I understand how all of those nice categories listed in the 3-pane format of 10.6 can be lumped into the less useful 10.7 version, but I do not understand how 10.6 knows how to tell a later program that it wants to revise the formatting that is arriving with the import. In other words, will just trying the expoert-import be risk-free? Than you.

Okay. It seems to have worked going from 10.7 back into 10.5, the only glitch being that I now have some duplicates, and I may have clicked twice (or I may not). When I elected to "review" the duplicates at the prompt, I may have been adding them rather than updating them. Again, thank you.