The Montreal Canadiens are heading into the playoffs with two rookie netminders, a rare occurrence in the NHL.
And although Jacob Dobbs and Jacob Fowler both lack NHL experience compared to most goaltending combinations, they have shown very encouraging potential throughout the season, and even more so since the Canadiens hired Marco Marciano as their goaltending coach on January 28.
Since then, both players have improved their 5v5 save percentages, and by quite a large margin too.
Jacob Dobbs goaltending statistics
As you can see in the table below, Dobbs' save percentage has increased significantly, but it is not due to any major defensive changes by the Habs. The Canadiens are forcing Dobbs to make more saves than ever before in both regular (SV/60) and high-quality saves (HD SV/60).
And yet, Dobbs has also significantly improved his high-danger saves (HDSV%) percentage, which is enough evidence to suggest that he is providing the Canadiens with better results than before while dealing with more shots on a nightly basis.

We have to take into account the sample size, as Dobbs appeared in 24 games before Marciano's arrival, and only 13 games since, but I'd argue that's more than enough to present that there's a strong correlation between Marciano's appointment and Dobbs' uptick in results.
Jacob Fowler Goaltending Statistics
As for the other first-year goaltender, he has significantly improved his save percentage while facing slightly more shots per game.
Fowler's high-danger save percentage has dropped slightly, although it should be noted that he is facing a 33% increase in high-quality scoring opportunities.

Montreal Canadiens Brass Tacks
It's very difficult to discern which improvements are simply due to the general ups and downs of a hockey season, and which are directly related to Marciano's work, but the numbers suggest that both of Montreal's first-year goaltenders have benefited from his presence, at least in the short term.
For example, Dobbs has also improved his save percentage on the penalty kill, which started at .812 before Marciano's arrival, and has since increased to .868.
The real test will be when the Canadiens start making a push in the playoffs, but as things stand, the team can be confident they made the right decision based on all the available data.
All Montreal Canadiens goaltender stats are 5v5, via Natural Stat Trick, unless otherwise noted.

