These days, Burns (19-3, 14 finishes) looks back on the way he pushed his body to the limit by cutting weight to get down to 155 pounds as “a dumb mistake.” Living life as a man walking around at 188 to 190 pounds and a listed 5-foot-10 who needed to trim about 18 percent of his mass to make the contracted weight limited his potential.
“I couldn’t take short-notice [fights] because I needed that time to diet and make the weight,” Burns said. “And that was damaging a lot of my performance because I had to run every single day.”
That's Burns talking about when he was a LW, from a 2021 article in the NY Post.
I don't dispute that Khamzat is taller, but clearly he was pretty much a skeleton at 170 compared to Burns (and compare to himself at MW), when it comes to body fat percentage and thickness.
Back in spring 2019, a few weeks after picking up a second-round submission win over fellow UFC lightweight Mike Davis, Gilbert Burns took his family on a vacation to the Florida Keys. The vi…
nypost.com
I genuinely believe they were close in weight, otherwise I wouldn't have said it.
Except this source, I also recall Burns talking about how he went into fight week at around 190, and I also remember Khamzat weighing about 190-195ish at WW, but by all means, ignore that if you like.