Volkswagen made petrol tanks with a 100mm filler neck until September 1952. From October 1952 to March 1953, the filler neck was 60mm to be changed again to 100mm from April 1953 to July 1955. 

So the petrol tank with a filler neck of 60mm (BBT 0492-070) will fit perfectly on your beetle with year of construction between October 1952 and March 1953 (better known as Zwitter models). 

The petrol tank with a filler neck of 100mm (BBT 0492-080) has the pressing around the filler neck. This is correct from April 1953 to July 1955, but of course this petrol tank also fits cars from August 1949 (VIN 116021) to September 1952. The only difference is that these had no pressing around the filler neck.