He actually has a decent chance at winning. No weapons against a being with some MCU worthy feats of his own. And although this is specifically Young Arnold Terminator, it's a T-800 and they're all built the same and all the Arnold Terminator's are basically the same guy from different timelines so the feats I believe at least track across appearances.
https://gfycat.com/creativehorribleblueshark - Pops T-800 holds up a bus one-handed.
https://gfycat.com/composedlateheterodontosaurus - Casually rips a T-600 in half.
https://gfycat.com/meagerweakhound - Original T-800 beats a door to death.
https://gfycat.com/oddglisteningairedale - Slings Rev-9 like a toy, one-handed.
https://gfycat.com/deadlydependentlangur - Tosses a guy across the room and he hits the wall, not the floor.
https://gfycat.com/polishedforkedboa - Sends a steel door flying
https://gfycat.com/wearyshowyfowl - Run over by an 18 wheeler.
https://streamable.com/tpnq - Was inside a fuel tanker when it blew up and was fine.
https://gfycat.com/elaboratejauntygypsymoth-arnold-schwarzenegger - Shatters concrete from hitting it, then smack a squad car hard enough to stop it. He's okay.
https://gfycat.com/heartfeltmadgermanwirehairedpointer - Eats multiple 40mm grenades.
https://gfycat.com/sandyreflectinganaconda - Even the act of two T-800's locking up cracks concrete beneath their feet.
A lot of the stuff he's done or tanked would seriously injure or outright kill Cap and Bucky.
Tough one. I think the team will struggle to inflict serious damage with just punches and kicks, but they might be able to do something if they use teamwork and combine their strength (like one grabbing the Terminator's body and pulling one way while the other tries grabbing an arm and pulls the other way or something). How powerful Bucky's vibranium arm is can also make a difference. Unfortunately, it's currently completely featless, so we'll have to wait for The Falcon and The Winter Soldier to see how it stacks up. On the flipside, the super soldiers are much faster, more agile and more skilled, so the Terminator will struggle to land a lot of clean hits IMO, especially if he has to contend with both at once.
I'd go with Team due to reasons mentioned mainly being able to overwhelm and coordinate together with strength thats not to far off but getting though that durability is going to be a problem.
1 v 1 h2h I can see the terminator winning a majority though, especially with combined feats(As Khazars said recent movies have really juiced up the feat list).