No, we wouldn't have. The underlined sentence is one of the reasons why we wouldn't have and why the trade for Roy Williams.
The Cowboys believed, as most of us did, they were superbowl contenders that year. That roster was the result of the rebuilding process that started with Tuna coming over. T.O. was supposed to be a final piece to that puzzle. Drafting a young, inexperienced WR who needed to time to mature ( as the overwhelming majority of receivers do ) was not feasible because they already had at least two of those on the roster ( Austin and Hurd ), so they decided to go with a veteran that was still young, but had experience and talent. The thinking was to keep the continuity with Romo in case T.O. got injured, while at the same time not having to go through the growing pains of a young WR. In short, Roy Williams was supposed to be the #1 WR for the long term and the #2 WR, back up #1, in the short term.
It was a sound theory on paper, but not a practical one. One reason for that is that RW isn't the typical #1 goto guy because he doesn't demand the ball like most #1, alpha male receivers do. That's not his personality and his game reflects it. Another reason ( and this is probably the most important one ) the Cowboys simply had more talent than pass attempts. Not only was T.O. going to get the bulk of passes for WRs, but Jason Witten was going to get just as many if not more of the looks, and Crayton was going to get some looks, and, at the time, Marion Barber was going to catch passes also. Adding RW to the mix didn't or doesn't " produced " more passes, he just simply took from others. The only way to fix that would have been for the Cowboys' offense to turn into a run-n-shoot system, and they weren't about to do that ( check the pass/rushing ratio for both 2008 and 2009 ). By the way, that's the same reason why people who criticize Marty Bennette for " not catching more passes ", have no clue of what they're talking about. Even if Bennett was the second coming of Tony Gonzalez, we would have never known it because he'd still wouldn't have seen many passes thrown his way.
The simple truth is that the Cowboys took a shot at finding a potential, long term #1 receiver and it didn't work out. Here's the breaking news: it happens all the time and to every team. However, they still found one in Miles Austin, who the crazies in here are now starting to complain about, and it didn't cost them anything, so at the very least they're even.