CONSTRUCTION
The cost to create given for each golem includes the cost of the physical body and all the materials and spell components that are consumed or become a permanent part of the golem. Creating a golem is essentially similar to creating any sort of magic item. However, a golem’s body includes costly material components that may require some extra preparation. The golem’s creator can assemble the body or hire someone else to do the job. The builder must have the appropriate skill, which varies with the golem variety.
Completing the golem’s creation drains the appropriate XP from the creator and requires casting any spells on the final day.
The creator must cast the spells personally, but they can come from outside sources, such as scrolls.
The characteristics of a golem that come from its nature as a magic item (caster level, prerequisite feats and spells, market price, cost to create) are given in summary form at the end of each golem’s description.
Note: The market price of an advanced golem (a golem with more Hit Dice than the typical golem described in each entry) is increased by 5,000 gp for each additional Hit Die, and increased by an additional 50,000 gp if the golem’s size increases. The XP cost for creating an advanced golem is equal to 1/25 the advanced golem’s market price minus the cost of the special materials required.
It doesn’t say that a homunculus or shield guradian is (within their description in the MM (or SRD) though.
From SRD Homunculus and shield guardian:
CONSTRUCTION
A homunculus is shaped from a mixture of clay, ashes, mandrake root, spring water, and one pint of the creator’s own blood. The materials cost 50 gp. The creature’s master may assemble the body or hire someone else to do the job. Creating the body requires a DC 12 Craft (sculpting) check or a DC 12 Craft (pottery) check.
After the body is sculpted, it is animated through an extended magical ritual that requires a specially prepared laboratory or workroom, similar to an alchemist’s laboratory and costing 500 gp to establish. If the creator is personally constructing the creature’s body, the building and ritual can be performed together.
A homunculus with more than 2 Hit Dice can be created, but each additional Hit Die adds +2,000 gp to the cost to create.
Craft Construct, arcane eye, mirror image, mending, caster must be at least 4th level; Price — (never sold); Cost 1,050 gp + 78 XP.
CONSTRUCTION
A shield guardian is built from wood, bronze, stone, and steel. The materials cost 5,000 gp.
The creature’s master may assemble the body or hire someone else to do the job. Creating the body requires a DC 16 Craft (blacksmithing) or Craft (carpentry) check. The keyed amulet is fashioned at the same time, and its cost (20,000 gp) is included in the cost of the guardian. After the body is sculpted, the shield guardian is animated through an extended magical ritual that requires a specially prepared laboratory or workroom, similar to an alchemist’s laboratory and costing 500 gp to establish. If the creator is personally constructing the creature’s body, the building and the ritual can be performed together. A shield guardian with more than 15 Hit Dice can be created, but each additional Hit Die adds +5,000 gp to the market price, and the price increases by +20,000 gp if the creature’s size increases to Huge, modifying the cost to create accordingly.
CL 15th; Craft Construct, limited wish, discern location, shield, shield other, caster must be at least 15th level; Price 120,000 gp; Cost 65,000 gp + 4,600 XP.
Now as I read it for a golem is subjected to a dispel it’s magical properties are suspended for 1d4 rounds. Basically it cannot move or act. Whether or not it reverts to a lump of material or just stops moving is up for interpretation. But since
The characteristics of a golem that come from its nature as a magic item then none of them should work if the construct is subjected to a successful dispel magic.
As far as the magic immunity property of golems it only works against spells that are subject to spell resistance and dispel magic is not. So it should work.
If anyone can find something more specific please point it out to me since this is indeed an intriguing question.