Question about pre-loads on Steam

If it did infact register on steam, I dont see why not.

Im pretty sure some games sold in boxes require steam to play them.

Majority of retail games that have a required Steam install (I.e. won't work without it) generally will install before a game's release. However they tend to be missing a file or two which is then patched on release day to allow the game to work. Valve have been trying various way's of stopping early game play however so this may be different to how game's such as Borderland's 2 will work. They may simply try the good ol' GfWL way of doing a date check.

I would like to point out though, that your saying you would be using a key from a retail box, would it not be far easier to simply install from the disc as most Steam Retail release's will come a disc install for Steam and the game content along side the Product Key.

It's pretty simple: if it uses Steamworks (meaning it requires Steam) you'll be able to install it but not play it. It uses the same protection as if you had downloaded the game from Steam itself... I don't know exactly what they do and I do know the game cracking scene has bypassed it plenty of times (Skyrim being a good example), but without such a crack you will have to wait until release date like everyone else.

The box will tell you if it uses Steamworks, though pretty much every PC game these days with a retail store release does since they're also usually major titles. Another easy way to know is if it's also available on Steam, as then it's probably a Steamworks game. Borderlands 2, for example, is such a game.

maybe i'm being a nazi here, but my mind instantly jumped to "your supposed uncle is breaching street date, and I hope he gets busted and fired"

If you've got the disk, you've already got the pre-loaded game.