I have a difficult time imagining that Redclaw would be the same guy as the original LBT sharptooth. Different skin color, eye color, and Redclaw doesn't keep his right eye shut most of the time (why did the original sharptooth do that, anyway? We seem him closing that right eye even before he gets into the briar patch, and yet his right eye never appears injured). They look too dissimilar to be the same character. If I were to identify the LBT1 sharptooth with any of the franchise's subsequently appearing tyrannosaurs, it would either be Chomper's dad (still very improbable because of differences in personality and the way they relate to Littlefoot et al) or the green tyrannosaur from LBT6 (and one would still have to explain why that one didn't always keep his right eye closed).
I can see there being a possible connection between Redclaw and the LBT1 sharptooth*. Perhaps they were once allies---partners in crime, if you will. Unfortunately, that would be mere fan speculation.
*He really needs his own name...Singleye, perhaps?