You almost NEVER need new retainers unless one of two things happens.

Inspection shows the need for a replacement or you are building a very serious race motor with tons of spring pressure.

You also do not need locks either, unless inspection shows the need to replace some.

With the very mild, almost stock, cam you are looking to run you are fine with what you have unless you see something during installation that suggested you replace them.

I would suggest you replace the valve stem seals while you are there though and since you should replace the valve cover gaskets (they will probably fall apart if they are old, cork ones) get the newer steel reinforced neoprene ones.

Springs ENGINETECH ERV901 (already gave you the sealed power #)
Valve stem seals FEL-PRO SS70014 (stock type, all seals incl.)

Both at Rockauto.com

As for the valve cover gaskets

http://www.manciniracing.com/valcovgas.html

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.