There should be an engine id tag on the engine stating the cc.
Manufactured from late 1970 to late 1972 (model year 1971 to 1973) this would be a 1600 cc engine.
1971 or 1972
This would be the model year 1971 through early 1972 Type 1 Beetles with the "34 horsepower" 1200 cc engine.
This would be model years 1971 through 1972 1200 cc "34 horsepower" Type 1 Beetle engines.
According to Chilton's 1971 455 is 12btdc, but there should be a decal under the hood or even on the engine itself that would list this info.
My guess would be between 1971 & 1972.
Mantrap - 1971 1972-05-29 was released on: USA: 29 May 1972
Arctic Co-operatives Limited was created in 1972.
Catlow - 1971 was released on: USA: 1 October 1971 Sweden: 24 January 1972 Finland: 17 March 1972 West Germany: 23 March 1972 UK: 30 March 1972 (London) Portugal: 18 April 1972 Denmark: 29 May 1972 Norway: 5 June 1972
1971 AFC Championship Game - 1972 TV was released on: USA: 2 January 1972
Le casse - 1971 was released on: France: 27 October 1971 Japan: 4 December 1971 West Germany: 16 December 1971 Denmark: 27 March 1972 Finland: 31 March 1972 Spain: 1 April 1972 Netherlands: 27 April 1972 USA: 14 June 1972 Sweden: 24 July 1972 Norway: 7 September 1972 Turkey: 19 February 1973 Hungary: 26 July 1973
Because the previous system was very complicated and computers and calculators would have had difficulty calculating in the old system which was superseded by decimalisation in 1971.