The same IP address (216.177.153.128) hosts several other affiliated websites including cumblastcity.com, over40handjobs.com, ebonytugs.com, meanmassage.com, tugpass.com, and petite18.com, according to the domain registry. So, my guess is that it is not really some industry-wide talent agency, but just the operator of these websites looking to hire guys for a scene or two of their on-line porn. On the other hand, it probably is legit within these bounds.
While I can't speak for the straight porn industry (although I see no reason why it would be different), the three studios that hired me for (gay) hardcore porn approached me cold, rather than me contacting them. In the first two cases, they initially contacted me through my on-line profiles (other similar sites, not LPSG), and then we continued the conversation with official business email, etc. I'm not sure if they scouted on those sites, or had seen me around, and then recognized me online. (I suspect the later, since I had long before discovered that I was in quite a bit of softcore porn without my consent. So apparently I get noticed for some reason.) In the third case, a porn producer walked up to me on the street, handed me his card, and said "Call me. I mean it." Well, there is a bit more to it... I was at a festival, just trying to persuade people to vote in an upcoming presidential election, dressed in red, white, and blue spandex, swinging my big cock in form-fitting shorts to draw attention to this somber patriotic duty... (That was just over 4 years ago, apparently I didn't try hard enough. But at least I got a porn gig.)
But in all of these cases, I knew a specific studio that was interested, and could check out their website, see what kind of scenes they did, who else they hired, Google the contact's name, etc., before deciding I wanted to get involved with that particular group and exchanging personal information.
Perhaps it is unusual to get contacted cold, but almost all porn studios have a model application link somewhere on their website, and you have more control this way. You can pick out studios that make the kind of scene you would want to be in, and apply directly to them. I've never done this, because I mostly agreed to the unexpected requests to have a little fun, not because I was looking to do porn, although it did pay. I know a number of people that were quite successful applying directly to a studio they liked, and that's probably the "usual" way of doing it. But, if you do apply to the Big Stud Search, I would check out the affiliated websites first, to get a feel for what this is likely connected to.