Bucky Barnes is not a dandy.
Although he would rather not discuss his roots - talking about his Grampy would make for a very long and involved story that would involve Tony Stark freaking out and buying stock in Holy Water - he had been raised to be a gentleman and that included being a very well-dressed one.
(“That’s his story and he’s been sticking to that for the better part of a hundred years,” would be Steve’s comment on that.)
So Bucky decides he’s going to rock the long-ish hair and got it shampooed, conditioned and styled to definitely look less hobo.
(Steve may also have indicated a preference for the longer hair, especially when it came to Certain Activities that involved plenty of sighs, moans, purrs and other pleasurable noises.)
And Bucky also takes a look at what would now be their shared closet and gives a long-suffering sigh.
“Hey, I have emerged out of Khaki Hell™!” is Steve’s immediate defensive reaction.
“Shaddup, punk, we’re going shopping.”
The shopping involves a lot of articles of clothing that are definitely NOT khaki, shirts that would not weep trying to fit broad shoulders and muscled arms
(“Steve, they were LYING like rugs to you when they told you these shirts would fit. LYING. LIKE. RUGS.”
“Sergeant Barnes, we were trying to do a service for all mankind!”
“God bless America!”
“I am picking out all your pants from now on, Steve. And your shirts!”
“Um…. okay, I guess?”)
and got the Darcy, Wanda and Natasha Seals of Approval™.
“Buck, you’re checking my ass out again, aren’t you?”
“Baby, I have been deprived of that sight for over seventy years. Let me feast my eyes.”
“You’re welcome to touch too, y'know that, right?”
“Not in public!”
— The Blanket Fort Fluff Countdown To Civil War a.k.a. We’re Gonna Need All The Happy Fluff We Can Get Amirite?