Craft (seige engine) AND knowledge (engineering) required to craft Cannon Golem?

[Kalderash]

I'm looking over the crafting rules (and specifically, golem types) in preparation for playing in a new campaign which I'm told will have plenty of "downtime," and I've noticed something which seems to me to be a bit of an anomaly.
Assuming that character X wants to construct a golem themselves, from start to finish, that means that X must pass the mundane skill checks required to create the golem's nonmagical body before even getting to spellcraft and all the rest. In all cases I've seen but one (and to the best of my memory, this extends to other fields of crafting as well), there is either a single mundane crafting skill listed, or a choice between A or B. See the Clockwork Golem for one example. "Craft (clocks) OR craft (locks) DC 20"
The Cannon Golem, however, reads: "Craft (siege engine) AND Knowledge (engineering) DC 25." Is this intentional? Is X required to spend the time and resources necessary to succeed on two independent DC 25 crafting checks to construct one inanimate body? Is this unique, or are there other items which require multiple mundane crafting checks to construct in the RAW? Or is this a typo/has it been errata'd, etc?

[Jeraa]

All masterwork items require 2 separate craft checks to make (though both use the same skill). So there is some precedent for an item requiring 2 separate checks to create.

As for the golem, I can see a reason why - the golem itself requires Knowledge (Engineering), while the cannon requires Craft (siege weapon).

[Kalderash]

Thanks for the reply. I do see the logic in requiring in requiring both types of checks.
With that in mind, since crafting golems is identical to the process for crafting other magic items, does a constructed golem body need to be masterwork? Do I need to pass both craft (siege weapon) and knowledge (engineering) checks to construct the body, and then another craft (siege weapon) check to make that body masterwork? Is there second knowledge (engineering) masterwork check? Do I need to make four checks to construct a single masterwork inanimate body suitable for animating?

[Fuzzy-Wuzzy]

There is no requirement that the body be masterwork. Golems are more like wondrous items than weapons/armor. Admittedly cannon golems are weapons too, but if they had a special masterwork requirement they'd list it explicitly.