1994 Chevy S-10 Cylinder heads

We had to rebuild a blown head gasket on my dads truck. We got a new head from salvage. Told us that the cylinder heads were interchangeble as in they sent us the left head and our right(passenger side) needed replacing.
Now we find that the exhaust manifold for that side has warped and won't fit on the new head, when we try to get another for it they told us they are not interchangable.
Well if in fact the heads are interchangeble shoudl just an new right side exhaust manifold then fit it too.
Are they interchangeable(the heads?)