I'm working on SBC iron heads and I have a few questions about valve seals.
I've never worked on heads like this, only on Al heads and usually with bronze guides and positive type
valve seals.

I have got two types of seals for this heads (see picture below). If I'm right, blue ones are positive type
(they are fixed on guides) for intake, and white ones are umbrella type (they move up and down
with valve and are fixed on valve stem) are exhaust seals. Am I right?

Also, I have got only 8 small o-rings. Where should I install them? Intake or exhaust?

As a side note, I should say that valve springs and retainers are aftermarket and
there are no oil deflectors that go over the springs in stock applications.

Here is the pic:

 

Consult the seal manufacturer for installation instructions.

 

You are correct. You will not need the O-rings with your aftermarket equipment.
The factory often puts positive style seals on the intake side, and the umbrellas on the exhaust. This allows the exhaust some extra oiling for longevity under harsh conditions.

You may wish to run any combination of seals depending on your usage and results. Some dirt racers run with no seals on the exhaust side.
A lot of performance builders, including myself, use the positive style (Viton ring & band) seals on all of the guides.