Well, like more or less everything about Antony, it's quite hard to tell because you never know what to believe. Through the early part of the play, and after the murder, he doesn't really seem to make any distinction. Brutus is addressed foremost by Antony's messenger, and Antony shakes Brutus' hand first:
I doubt not of your wisdom.
Let each man render me his bloody hand.
First, Marcus Brutus, will I shake with you...
But this might simply be because Brutus has positioned himself, logically or otherwise, as the chief conspirator. And then when they've all exited, Antony damns all the conspirators in equal terms:
O, pardon me, thou bleeding piece of earth,
That I am meek and gentle with these butchers!
There's also the whole "Brutus is an honorable man" question - does he mean it? Well, obviously not, bearing in mind what he brings about. Yet he more or less echoes that statement, unironically, after Brutus' death, in the last speech he makes in the play:
This was the noblest Roman of them all.
All the conspirators, save only he,
Did that they did in envy of great Caesar;
He only, in a general honest thought
And common good to all, made one of them.
His life was gentle, and the elements
So mix'd in him that Nature might stand up
And say to all the world, “This was a man!”
High praise - great conspirator, and great man! But again, it's difficult to take that not with a pinch of salt, knowing what Antony thought of Brutus and the conspiracy. It's a complicated one - and, as you can see, there's no clear answer to your question - Antony does make a distinction, but does he make it sincerely? Who knows.