2006, Jeanine Pirro running for NY AG was given a C. She deserved an F as for years she used her office as Westchester DA as a soapbox for gun control. 2008, Sandy Treadwell was giving an A in his Congressional bid while his record as NY GOP chief at best suggested indifference to the issue. Plus he lied in a campaign mailer. From what I've seen, about 25% to 35% of their ratings are off, either too pro or too anti. In the NY-23 special Congressional election Dede Scozzafava was given an A, but that is a bit generous as while she voted with us against gun control, I can't recall her ever promoting pro-gun bills.
To be fair I don't believe all of this is deliberate. I do not think they spend enough time looking at incumbent records and I do not believe they research challengers enough to make informed decisions. Most of their endorsements go to incumbents and the bulk of them don't really need them. I suspect that is because they just don't have the ability to use their resources in the most effective manner.