Technical 1937 21 stud heads ??

Bought this 1937 rebuilt flathead a while back and has been in my shop for awhile now .I stumbled upon a set of aluminium heads (OEM) for it and notice the heads and water pumps are different ??
The rear of the heads have plugs in them also the waterpumps have plugs and grease nipples
What are they ??

 

Heater attachments and grease nipples for the pump shaft.

 

That's what I thought as well ,but not all 37 heads and pumps have them.
Ford special order ???
Thought maybe boat ??

 

That does not appear to me to be a ‘37 engine but rather one from ‘34-‘36.

 

It has the lower water pump covers on the front of the block ,guess it doesn't mean the heads aren't 34-36 was rebuilt by a ford approved shop and never used ...

 

37 was the only year that you could run either style of water pumps, and heads

 

Anybody able to shed some light on these heads ??

 

Could have been for industrial use. I have seen the early head- later block setup before. "Ford authorized" rebuilders did this a lot I'm told. I even have some iron early style "replacement" heads dated 1947