It's a good question. I tend to think that it's Carlie playing on that particular tune, but I'm not sure 100%. The drum players in pablo's original rockers album keeps being a mystery, at least for me. To the best of my knowledge...
Thunder Clap
This is the instrumental take of Horace Andy's Ain't No Sunshine, originally released in the 1973 LP 'You Are My Angel':
http://www.roots-archives.com/release/155, but I think the sessions took place in 1972. There are two tracks played by Carlie in that LP, Rain From The Skies and Dream Lover. I still got the doubt if Carlie plays in Ain't No Sunshine. It seems so.
Rockers Dub
Cassava Piece
Auntie Lu-Lu (by Junior Byles, not included in the album)
I think that these three pieces come from the same session and, according to the experts, it's Tin Legs the guy playing the drums on them. I think the raw cut of cassava piece is this one:
http://www.youtube.com/watch?v=xw1lsh6eERg. Before I first listened Auntie Lu Lu, I was quite sure that it was Carlie playing on them, who else could play these rolls in the snare and cymbals? But after I listened the intro of Auntie Lu Lu, I started to doubt that it was Carlie; after consulting it here in the forum, some people pointed to Tin Legs. I think the session also took place in 1972.
AP Special
I have no idea of (A) the date in which this track was recorded and (B) who is the drummer playing on that tune. It seems to be an early recording, 1972-73, but it's just an intuition, not a fact.
Up Warrika Hill
Tubby's Dub Song
I think these two songs were recorded in the same session, but I'm 99% sure that it's not Carlie playing on them. I don't know neither the recording year, maybe around 1974.
New Style
Jah Dread
I think that Carlie plays in these two songs. In Jah Dread for sure, there is no doubt about it. The presence of the cowbell and the hi-hat style reveal that it's a 1974 recording. For New Style I'm still in doubt, because it seems in certain parts of the song that the hi hat or the rolls in the snare, whatever, were added later to reinforce the rhythm.
Park Lane Special
This is another take of 'Judgement Dub,' a song that was (originally?) released in the 1978 LP Africa Dub and credited to Carlton Santa Smith.
There are some other pablo-related songs where Carlie is playing and that you could cover as well, such as: Pablo in Dub, Corner Crew Dub and Rockers Meets King Tubby In A Fire House (this one has a very strong rhythm and the hi-hat style is perfect). I hope you find this info useful, and if somebody in the forum could bring more light to this topic, you are invited to participate. All the best.