Whaaat?
What's simpler than swapping a hard-drive with a hard-drive from a machine that he got a few days ago? It's the same hard-drive, same size, speed and probably built by the same manufacturer - and they both run the same OS. Also, those restore disks have nothing to do with the hard-drive, and everything to do with the other hardware in the machine, ie; cpu, gpu, logic board, etc.
Right. The drive will work completely fine. If it's a bigger/faster drive, I would swap it too. And, you're also right - the restore disks have to do with the hardware. That's because they have the minimum system required for that machine. That build could be
newer than the public build of the same version (in other words, they could both be 10.5.8, but one machine could have a different
build of that version than the other).
But, I wouldn't bet on the
builds on each machine being the same. Why risk a world of hurt if they aren't? If the old drive is faster/larger and it makes sense to swap it to the new machine, the best method is still to use the Migration Assistant. Once everything is migrated to the new machine, then the entire volume can be cloned to the faster/bigger drive using Disk Utility's Restore function.
If the builds are the same, there's a good chance the swap will go ok. But, using the Migration Assistant takes the hardware difference out of equation.
That's my opinion, anyway. The OP obviously can read this (and other) threads and make an informed decision on the best way to go. I think they'll find this method has the best chance for a problem free transition.
Anyway, OP - enjoy your new MBP!