Hummm...
In the 737-200, you do can deactivate antiskid (there are two switches on the center panel).
I know you were talking about the Classics - since I've never flown it, I couldn't assure that it is possible to turn it off. But there is a switch too (only one in this case) - what is it for?
You could check it on
http://www.b737.org.uk/centrepanel.jpg
Cheers,
PP