i no longer live in the area, but it was my observation in the three seasons from the 2004 to 2006 (when I did live there) that the window of "ideal" flow got a little smaller each year. in 2006, i personally felt the ideal flows were 3400-3600, and it was completely gone below 3000 and above 4000. even at 3200, it is somewhat inconsistent between green with no break, and having only a small foam pile. 3600 is the best level IMO, with consistent break forming a nice foam pile on top.
seems early, but the glenwood guage site should be free of ice and obstructions, so if it saying 3350 it should be accurate. it may just be a spike from warm mountain weather, and may not last through the w/e. call glenwood canoe and kayak before making the drive, quite a few of those guys are regulars when the wave is in.