Yup, I did a bit of checking and I think you are correct that they are the same as the ones branded as Easy-build and pre-built ones. Not a bad idea actually, as I damn-near went blind fixing the planes onto the sail since they are only about 3-4mm wide!
For the size they are quite detailed, although in the case of the Oyashio, with its hull-mounted sensors, the split for the two halves of the hull in kit form could not come in a worse place, as in sanding the join prior to painting, it is virtually impossible to avoid wiping out some of the sensor detailing, but, enough remains for it to look reasonably okay. I'd recommend these if you have a spare hour or two, as that's really all it takes to knock up something pretty decent-looking, and with some careful painting, I imagine it will make a nice thing. For 3.99 in the UK, you can't really argue.
Chock