there was no standard on how 'dark' these needed to be to pass. bunch of them were take-offs, re-arsenaled, re-issued, re-used, bubba-ed, etc. i've seen krinks in the Ukrainian storage depot that were all shades of brown to yellow-grey. yellow ones were those with shellac almost completely worn-off. i've seen some really dark ones from being held by dirty hands and then re-arsenaled over with shellac with just minimal cleaning. i've seen like new rifles with well-worn handguards and the other way around. but majority looked like light-brown to dark-rich amber. what you have in hand seems like an average representative of the breed. i wouldn't sweat it, personally.