Hey guys I'm new here. I work a a truck shop and I now own a mac tech 1000 and just have some questions that mabey somone could answer. First off is can I upgrade to the spring loaded casters? Second is I think it an older version because it seems that small screws hold the sliders to the drawer so mabey the age range of this box? I paid a grand for it and its a great box (course i have a prefrence for mac tools, well not as much as I used to due to there mase in china **** but still) and final question is was this box mad in there george town ohio plant?