Originally Posted by Molokov
Generally speaking, no. The only way Telltale knows that you have bought one of their games is if you buy it directly from them. Buying through other means still gets you the downloadable games but unfortunately you're not eligible for the DVD.
I think for /one/ of their titles (ToMI or S&M:TDP, can't remember which), they managed to tie things in with Steam but considering I don't use Steam I don't really know.
I recall it was for TDP, but it wasn't for Steam users that wanted the free DVD. It was for PC users that wanted the TF2 Max Hat. Anyone got the game from Telltale Store got the same game on their Steam account. But Steam buyers couldn't get the game on their Telltale accounts, sadly.
No, Steam customers usually can't get the DVD.