Part is mentioned in the manual for the Beetle until 1952 and the Barndoor parts manual untill 1954.
This MANN fuel filter is commonly seen on Porsche 356 Pre A engines.
Tuners like Denzel and Okrasa also used these on there engines.
Numbers as seen on the lid are: BF329 & KD 08.49
Used from Engine number 20 – 518 652 (12-1952) up to 3 999 999 (05-1959) Carburetor with accelerator pump, without automatic choke, with the threaded fuel line connection 6mm.