Replacing Exterior Door Jamb

I have a rotted exterior door jamb that I want to replace. I did this once a while back and I'm trying to recall what I have to deal with.

I need to replace the hinge side jamb of a right hand door that opens to the house. I have a spare jamb, pictured, which I took off a new door a while back.

But I'm thinking that what I have in the pic is a lock side jamb...(because one end is slanted on the wrong end, vs what I need for the hinge side)


Straight End.


Slanted End.

Am I perceiving this right?

Can someone help me tease this apart? Or else can I get a generic exterior jamb from the lumber store, then tweak the ends as needed? Thanks!

ps I'm not interested in replacing the entire door.

 

Yes, that's the left jamb (viewed from outside) on your RH door.

 

Door threshold always slopes from inside the home to the outside, so the jamb piece in the photo can only go one side without changing the slope on the bottom of the jamb piece.