Sure, you can do that. Whether you have to worry about offset depends on the type of wheel you want to put on in place of your current wheels. If you want to go with “stock” Mercedes wheels made for any year r129 (or for other Mercedes models that happen to fit the r129), the offset will be correct and nothing to even think about. But if you want wheels not specifically made for the r129, you’ll have to be sure they fit and offset is one of the parameters you have to get right. Do you know which wheels you want? And what size/type are your current AMGs, if I may ask.