You asked about Long Rifles, so, if you look at say pre 1850, east of the Mississippi, Long Rifle style Rifles, I'd say about 99% of them were made with a cheek piece.
Certainly you'll find the oddball once in a blue moon with no cheek piece, but from what I've seen, ( my Free opinion
) even the cheapest back action hardware store clunker had a cheek piece.
Move out of those parameters to a later time, out west, non rifle, non longrifle, and you'll find a different story.
John