Are all years of bravo 1 uppers and lowers interchangeable?

I've been interchanging them for years. You just need to plug the oil transfer hole in either the upper or lower if the other side doesn't have a mating hole.

Thanks!

A tap for 5/16 course thread fits perfect in the hole with no drilling. Then locktite in a SS set screw. Before tapping I put some paper towel down in the hole to catch the chips then use a shopvac to suck out the chips and papertowel when done.