Looks to me like a four wheel (4 legs, with front wheels at two short legs/ends on a front stabilizing crossbar).
That's the middle one in my links, above.
Works fine on level smooth-surfaced floors. Much better than the first two links above it. But, I'd not use it moving an engine out to a slightly sloping rough tarmac driveway.
The three-wheel ones are the "killers" with stovebolt 6 engines. They are about $10 less expensive than the one you have - it would be silly to save that $10.
