A `72 1300 would be a Standard Beetle made for the European (possibly Canadian) market, where vehicle excise tax is affected heavily by engine displacement. The engine displacement could be 1200, 1300, or 1600cc in such a car - they had options, where in the US we always got the largest engine offered. The engine codeletter/serial number is stamped just above the dipstick, what is it? The VIN is stamped into the chassis under the rear seat (just forward of the shift coupler access panel) and on a small aluminum plate riveted into the trunk. All cars sold in the US after Jan 1 1969 also had to have it in the lower corner of the windshield (another riveted-in tag) and on the driver's side B-pillar (tamperproof metallized sticker) although I don't know if a non-US-market car would have those. You bought a car without comparing the VIN to the paperwork? NEVER do that...I hope there's no problem.
This is quite likely a swingaxle car (last year for swingaxle in US was 1968). Are the rear axles inside fat tubes or are they exposed shafts that you can see rotate as the car is rolled along?