I'm sure it was an honest mistake. You included that clip in the same post as your jab example, and offered it as an example of an impressive combination.
When Dillian Whyte varies his punching speed, it's praised because it makes the punches harder to anticipate. When Corbett does it, it gets criticized. That series of punches would not look slightly out of place in the current division
He was two pounds overweight for the lightweight battle against Gans in 1903 so pretty darn close. Gans manager made claims that Sam was in the 140's. But he was close regardless. According to several sources, he was listed at 133 later that December.
According to the Boston Globe he'd spent the morning trying to drain down to the limit, and 140 was as low as he could get. Honestly I didn't realise it was at 138Ibs, which is a bit of a stretch for Lightweight, especially considering the title was still being fought at 133 ringside not long after. What sources list him at 133?
Well, Sam fought well above 175 pounds. Above 200 too. Keep in mind back then people like Johnson Dempsey, Louis, and Marciano all won the title UNDER 200 pounds. If you want to use that logic, then many past heavyweight champions, the names I mentioned above would be best suited for the cruiserweight division limit of 200 pounds.