Convertible top tack stick screw question

[KevinW]

So I picked up some vert parts at a local swap meet.  Both my 69 Camaros have a thicker bolt to hold the lower tack sticks (staple edge of canvas top to, then they get screwed to the body).  I needed a couple more for my set and they were in the bucket.

But the bucket also contained these thinner screws that are the correct length.  I see the ones they sell repro are also thinner.

So what sizes are 67 & 68?  Also maybe these thinner versions are for other body styles and the repro catalogs just say they will also fit F body's?   

I feel for 69 vert owners that order the repros and they do not fit the factory holes