The consensus on the Mocks and on the site is that the two guards won't be available when the Cowboys pick at 18. For that to be the case, more than 20 years of drafting history will have to be overturned.
So far this century, no G has been drafted before the 15th pick. In those 13 drafts, only 4 guards have been picked before pick 18 (picks 15-17). In each of those cases, the next guard was not taken till the 2nd round or later. See below for table.
Bottom line, there have not been two Guards drafted inside the 18th pick since 1988 - 25 drafts ago! (Dave Cadigan at 8 and Eric Moore at 10, by NYJ and NYG respectively. Ironically the best guard that year was taken at 19 - Randall McDaniel - so who is the next best guard after Warmack & Cooper?....)
That is a lot of history to overturn. Many Guards have been touted as top 10 picks only to fall on draft day. David DeCastro being Exhibit A. Furthermore, the Guards have proven to be pretty safe picks with the vast majority proven to be very solid players starting a number of games for their teams (with DeCastro being an apparent exception at this early stage)
Maybe history will be defeated this year. It is a very strange draft with an almost total absence of high quality offensive skill position players (QB, WR, RB).
But count me as among those hoping we do get one of those Guards at 18. History suggests at least one of them will be there - Question is, will the Cowboys take them if they are there?