Yes , although the actual difference between a 60 spring length and 70 is 4mm(according to TLC FAQ). I had 60 series and 75 series Dobinsons suspension on my 73 series.
The only thing I would be wary of is some heavy duty 60 series leaf springs will be a bit hard for a MWB. You could take a leaf out or ask for standard duty.
If you want to check for yourself ,compare the part numbers on Dobinsons page, I'm pretty sure the 60 and 73 series had the same part number in their catalog.