I haven't seen the Oddjob klicky myself, but according to Catchet (via SonParaMiHijo) on klickywelt, his "hair" (the black skullcap thing) is non-removable. that is a shame!
I have a few Oddjob klickies. The black piece on the head is
removable and it does fit on other klickies´ heads.
But the head from Oddjob is smaller (less high) then normal heads, about 2/3 I would say.
The 'hairpiece' from Oddjob does fit on regular heads, but to create a 'clean' bald-looking effect (but with a hat on top) one should use an old klicky (from the 70s or 80s) that comes without the side-provisions to hold beards, witch-noses, glasses and such. (Of course unless beards, noses or glasses are desired).
With some 'regular' hairs, Oddjob looks quite weird because of his small/low head.
I took a few pics but can´t post them here because even after resizing they are much more then the allowed 100 kB limit.
And I don´t use hosting-platforms. (Those disappear or become paying sooner or later.)
So I´ll put them on my FB profile-page, that might help some of you.