If you sit down with one of each copy of AL (AFAIK any 2 copies), you will find minor tweaks and changes to the attack tables in every one. I recall discussing this about a year ago, and we found that between 3 editions ('89, '99 and '03) and 2 printings (A UK printing, and a 2nd US printing) we found at least one attack table had been fiddled with each time the books went to press. So you could have 3 Arms laws with exactly the same cover art and text content, a US 1st edition, a US 2nd printing, and a UK printing and each one will have some slight variations in the attack tables somewhere. . .I can't recall any of them being major, more akin to "Qarterstaff does hits 5 points sooner on the table" or the like.
I'm not aware of anyone making a study of what all the little changes are.