Ineligible receiver catching the ball

[will27]

In today's Jets-Chiefs game: QB threw a pass that hit Jets center in back of helmet, ball popped up in air...
Jets OT slapped the ball down...no penalty.
If he had caught the ball, would it have been a penalty?

[APG]

ARTICLE 8.  ILLEGAL TOUCHING OF A FORWARD PASS.

It is a foul for illegal touching if a forward pass (legal or illegal) thrown from behind the line of scrimmage:

(a) is first touched intentionally or is caught by an originally ineligible offensive player

[will27]

Thanks.
It pays for O-linemen to know the rules.

[ChicagoZebra]

Isn't the subsequent slap down an intentional first touching by the ineligible offensive lineman?

Or does the first unintentional touching make this okay? 

[WingOfficial]

Isn't the subsequent slap down an intentional first touching by the ineligible offensive lineman?

Or does the first unintentional touching make this okay? 

Based on my reading of the rule APG cited, it would seem that the first touch was unintentional (the pass hits the back of his helmet), and so all subsequent touching is not deemed illegal.  (But if he had caught the ball, it would have been illegal)