No mens, matchmaking uses your skill rank (master guardian) AND your TRUST FACTOR, which is a score impacted by how many, hours, games, reports, and praises you have gotten in game.
Btw, 400 hours are REALLY low hours 'round here with some of these nut jobs from hltv, including me. For them try harders(read, not casual players), 2K hours, is below average, 5K hours is above avg I think, 10k or more, is about Pro player numbers, some having 15k+. Tho, obviously, hours don't really mean shit.
I personally would expect something like:
about 1000 hours: Gold Novas (4 stars ones)/MGs
about 2000 hours: LE/LEMs (legendary eagles/masters)
more than 2500 hours: I would expect the person to be SMFC(supremes) or globals.
Which when you get here, hours dont mean much, and ranks even less, as most tryharders/competitive players play FACEIT (where most globals are about lvl 4-6. 7 if they're good, max lvl 10), and if you are a Brazillian, probably GAMERSCLUB is the best option (where globals are about lvl 13-15, 16 if good)