Good eye. It does say "GOVT EXPER with OSS" (emphasis on 'with') rather than "XYZ of OSS", implying some sort of external role – such as helping establish chain of command in the early days, or some other bureaucratic help. A glance at the register itself shows that most OSS involvement is cited with the "of" convention: https://archive.org/stream/biographicregist1950unit/biograph... (BR, 1950 edition)

The distinction of "with" and "of" is interesting in itself. I guess he may have coordinated external logistics or something else during the war for them. '41-'45 is a long involvement, either way; surely he knew plenty of people there. Makes me wonder about the motives for bringing up his name then dismissing him as anything but career foreign service in the original article.

And that's exactly what makes spy work so interesting to observe in the first place: trying to figure out the motives, reality vs. cover, intent, etc. of complete strangers. It's all fun and games until you become their target, I suppose.

I always assumed if the CIA recruited someone from another government agency for covert activities, the recruitment would be "dotted line" on paper, i.e. that person would officially still work for the military, FBI, State Dept or whatever.