No. It's pronounced Fronkensteen.
4 seconds sound clip from the Young Frankenstein (1974) movie soundboard.
You can hear this line at 00:15:44 in the Blu-ray version of the movie.
Quote context
[...]
- No. It's pronounced Fronkensteen.
- Well, why isn't it Froderick Fronkensteen?
- It isn't. It's Frederick Fronkensteen.
- I see.
- No, it's pronounced eye-gor.
- But they told me it was Igor.
- Well, they were wrong then, weren't they?
[...]