Type libraries generated by TLBEXP can have identifiers that differ by case:
http://social.msdn.microsoft.com/Forums/en-US/clr/thread/5003c486-ed3f-4ec8-8398-a1251b0f9e74
I've also noticed that the order that types appear in the exported type library can change from one build to another.
Does anyone know of a tool to compare type libraries?
I found one here: http://www.oberonplace.com/products/tlbtools/index.htm but its comparison is case-sensitive so it throws up spurious differences.