I don't think its possible to type a strain based on looking at a half-erupted sprout.
As mentioned, the term "lambs bread" (sometimes "lamb's breath") was used by Bob Marley and others to refer to their favorite strain from the 1970s, which presumably would have been among the best of the heirloom strains grown in Jamaica at the time. That's probably a long-flowering low-yielding Sativa plant, not well suited for indoor cultivation under lights.
Also, frankly, its not clear to me how many strains are growing native in Jamaica or how different they are. My understanding is that there are lots of clandestine (and not so clandestine) fields of the stuff growing and lots of its gets cross-pollinated. The traditional Jamaican heirloom strains (ie "landrace") have likely been corrupted by influx of faster-breeding/higher-yielding Dutch genetics in the last 10-20 years. So any random weed you buy there is likely to be just that. . random. The average grower there probably just calls his stuff "ganja" and grows it from whatever seeds were left over from the previous crop.
The likelihood that some seeds you buy from some guy on a beach are going to be genetically identical to what Bob Marley talked about in the 1970s is pretty slim.