>>8905762At one point all Mandolorian Armor was Beskar, but it was something you had to earn. After the Empire, Beskar was somewhat rare and hard to get ahold of so most Mandalorians had armor made from other materials if Beskar wasn't available. Its also part of why handed down Family Armor was kind of a big deal. As for Din not painting his armor, the colors Mandos paint their armor have meanings and Din might have just not had an reason to paint his armor yet. Given his attachment to Grogu and having to let him go he might add a color or two in the next season.
And Din wasn't the first guy to just stick with the unpainted Beskar look.