The top rib of a Meriden built Parker GH/GHE with fluid steel barrels should have a barrel stamp that contains exactly the following "Parker Brothers Makers Meriden Conn. Parker Special Steel". I have seen some Remington era Ilion guns that had no stamping at all on the rib.

I would be suspicious of any Meriden era gun without that rib stamping as it may have been a rebarreled (non Parker barrels) damascus gun.