Stock heads?

Hi guys, we bought a 90 5.0 HO and drivetrain for a 66 Mustang.

So far, we've found MSD ignition, headers, E303 cam (I think) and a T5z; which makes me question if the heads are aftermarket or not. I know that there should be some type of E7 casting SOMEWHERE, but without removing them, I see nothing.

The only available codes are:
On the drivers side head I can see these:
29549
1510C
1 1/2
(1 or T)-4
(B or 8)J28

and on the passenger side:
29105
1510C
1 1/2
(1 or T)-4
(B or 8)H14

and a few pictures...






Thanks for your time!
-Dave

Thanks! Just wanted to be sure. I usually work on engines with 6 or less cylinders, and this is my first domestic; just wanted someone in the know to check it out.