'67 108? 280SE? Hmmm, it's either a 68 280SE (or later) m130 (straight 6) with mechanical injection (did they have air temp sensors?) or a 67 250SE...
Sounds like someone replaced your air filter assembly at one point with one from a 3.5 or 4.5 in which case you needn't worry...

Or, someone replaced your engine, or someone told you the wrong year? You have the m130 I6, or the 3.5, or 4.5? (3.5 would be a Euro if 108)... 4.5's started in '71.