One of the major differences between shared_ptr and CComPtr is that shared_ptr is non-intrusive - it can manage anything, even things like ints that don't know anything about strong/weak refcounts.
Nonetheless, the concepts revolving around CComPtr and all that good stuff can be easily seen in C++98 / STL. STL Strings for instance automatically clean themselves up under the principles of RAII.
Auto_ptr<>, the first smart pointer, also was standardized in C++98. While crude and primitive by today's standards (especially compared to unique_ptr<>'s explicit RValue semantics), auto_ptr<> shows me that even in the mid 90s, people understood the principles of RAII.
At least, if you were a learned C++ programmer.