I haven't seen the full Ragman's Roll but I do know that I did not see any Caldwell's on the Ragman's Roll for Ayrshire. There were three Colvyle's (various spellings). The court language of the time was French and this may have been a scribe's corruption of Caldwell or on the other hand they were most likely from the noble family of Colville also established in Ayrshire.
The fact that Caldwells were not on the Ragman's Roll does not necessarily mean that they were proud patriots refusing to bend the knee but more likely they were thught not to be important enough to be required to sign.