I'm not worried about how Noteboom and Allen will play. It's not like they're rookies and the Rams are projecting how they will transition from college to the pros. These guys have had a full year with the team.
Boom was one of 3 OL who did not allow a sack or pressure last preseason. Going on memory he had 79 snaps and the other 2 guys had something like 12 and 15. Boom and Allen got practice reps with the 1s every Wednesday, I assume going against AD, Suh, and Brock. And they had some live game action. If the Rams had any concerns about these guys they would have retained Saffold and/or signed an OL or 2 in FA and/or drafted OL high. Since they did none of these things that means the Rams (specifically Kromer) have given these guys their seal of approval.
Could they be wrong? Sure. But Kromer has a great track record and he has a substantial amount of hands-on data on which to form his opinions.
AlbaNY_Ram