My experience with Jamaican, the kind you get from rastas around the blue mountains is a very sativa variety, with long dready calyxes (just like the hair styles of their cultivators 
). But the ganja is somewhat mild in effect — though it still has a good ceiling.
If the bud you remember has a more hashy appearance like most post-dutch stuff, then I would guess it is probably a cross of one of those island strains to a Dutch strain.
From what I know, Jamaican landrace is likely related to Colombian landrace, and I think they have similar characteristics. But they won’t form the kind of dense nugget buds, because in hot humid climates, those structures are too prone to mold.