What heads are these?

GT40 heads have the 3 bars on the front and GT40P heads have 4 bars. Under the valve cover you may see a GT40P there, but not 100% (Seen them with/without).
Casted into the lower head bolt by cyl#s (1) or (8) -there is GT for GT40 heads and GTP for GT40P heads.

The E7 heads are typically identified by removing/confirming the E7TE Cast into the Exh. side- bottom of the Head-Head removed....But, A mirror or small Borescope with an attachment Mirror may also allow you to view the ‘E7TE’ cast into the exhaust side, on the Head bottom, while installed.
If you don't identify the heads as being either GT40 or GT40P heads then there's about a 98% chance that they're E7 heads. Rare, yet possible non E7 if someone was building the motor with whatever available 5.0 Parts were on hand. Good luck! J

It's not too often someone changes the heads, but not the headers.