Can anyone out there tell me if there is a way to identify the BF400 and BF500 FEL's. My serial# is still readable but not the model# I need to replace two of the hard lines and need to identify which model I have. This is on a model L235DT early to mid 80's not sure of exact year. Factory was able to tell me s/n was good for both the 400 and the 500. Any physical differences that would help me identify this would be greatly appreciated. Love this thing, one line is now leaking and second one is not far behind due to rubbing against each other. Thanks to all who offer any tips!