There is no such thing as 'correct' pronunciation of any language just as there is a wide variation of pronunciation amongst native speakers of english. An english speaker, unless very fluent in another language, will generally mispronounce the other language compared with a native speaker and vice versa.

Sako, Brno, Mauser, Kahles, Swarovski, etc are all mispronounced by english speakers compared to their native language speaker but how english speakers pronounce them is not correct or incorrect it is what it is.