Noteboom started all of the Rams' preseason games in 2018. I'm pretty sure the Rams were the only team not to play their starters in the preseason that year so it's a safe assumption that 'Boom faced the starting DL for the Ravens, Raiders, Texans, and Saints for however long their starters were in.
How many snaps that was I really don't know. More than zero for sure And no pressures. (Personally I see that as a positive.)
Also, there's the 47 snaps against the 49ers in the last game of the season. The Rams didn't play their starters but the 49ers did so that's another body of work to evaluate.
In addition, 'Boom took the starter's reps at practice every week in 2018 due to Whit getting his vet days off. And although we as fans don't get to see how that worked out the coaches certainly did. They had been pretty outspoken about 'Boom's potential at LOT before his injury.
As a result of what limited info we have it seems to me that Noteboom is a better tackle than guard. If you don't think so that's fine.
AlbaNY_Ram