Your original post a while back was that you were buying the Sako, and
Most of us have been quite on your questions, because no one quite knows where to start. Depends on what you mean by "acceptable." Will they let you shoot? Probably. Will that Sako do any good? Extremely unlikely, if you're talking benchrest.
In benchrest, Sacramento is NBRSA country, and NBRSA long ranges is sort of, uh, small. About as many people at the nationals as most of us get at a match. On the other hand, if you're not talking benchrest, then I (for one) don't have any useful information for you.
Most 1,000 yard competition is shot under IBS or Pennsylvania sanctioning. Here is a link to the IBS 1K results, and many match reports include an equipment list
http://internationalbenchrest.com/results/long_range/_longrangeindex.php
And here is one for Pennsylvania.
http://www.pa1000yard.com/
You'll have to prowl around to find equipent lists, but they are there.
I doubt you'll find that Sako either place, which should tell you something. You also won't find many .338s, but I happen to be one who shots one in Light Gun. And find that my 15 years shooting 1,000 yard benchrest might have prepared me to *learn* how to shoot it, but it is not a matter of just picking up a new rifle & going to shoot. I mean that seriously. I've borrowed rifles to use in a shootoff when I was out of ammunition, and won. A .338 is different.
I don't know who at Sacramento was recommending the Sako TRG-42 in .338 Lapua, but it would be close to my last choice, even with a Factory rifle.