The easiest way that I've found to make sure that icons and the like are present is to choose a Mek of the same weight and general appearance (one that you like, presumably), then modify that file instead of creating a brand new one.
Also, in MekLab, make sure the "Year" field is set to the Era you want to play in, or before.
Also, in MegaMek, check to make sure that "Canon Units Only" isn't checked in Game Options.