L & I J White Plane

Picked up a L & I J White Buffalo ( stamped on the toe of the plane)
Is this a Plow Plane? I thought a Plow Plane had a adjustable fence?
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The Heel of the plane is marked 8/8.
What does this say about the plane?
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Also at the area (about an inch long) where my finger nail is, the metal is raised higher than the rest and is ground like a knife edge (two sided)
Is this normal ?
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Also the blade has a grove in it that kinda fits in the above Knife edge but does not look original.
Is it original? ( The grove)
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Some other photos.
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Cuts the groove for a Tongue & Groove joint
The groove on the back of the iron was made to fit the "knife edge" on the skate. Helps keep the iron aligned with the skate. Otherwise, the iron will move from side to side in a cut....bad for cutting a groove.
Grooves and mating knife edges go hand in hand, should be original to that plane.
Not too sure about all the marlings....some may be from another owner? The 8/8 may refer to how wide a board's edge this will work on....as in a 4/4" thick board's edge?

Now, all you need to do is find it's "match" plane that will cut the tongue.

Thanks for the info.
Never once considered it was part of a set of Tongue & Groove planes. Guess I should have looked closer at all the other planes there. Too late now. Picked it up traveling through Ohio Amish country.
Still, cool old plane to have in my collection.