Seems like the ET 40 will not work up front on the '72 1302 model as per the below and both these forums reference an ET26 as being correct for a '72 Type 1
https://shoptalkforums.com/viewtopic.php?t=144271and this excerpt from the below link:
"Volkswagen increased standard wheel size in March 1972 from 4J x15 to 4½J x15 and introduced the 5½J x15 Sports rim in 1973, originally for the Yellow and Black Racer and Sports Bug, with an initial ET 26 and soon changed to ET 34"
http://www.sebeetles.com/wheels/