Hugh -- my guess is that it is subtropical rather than tropical due to the wind field, with the strongest winds all to the north of and somewhat removed from the center of circulation. Phase space analyses suggest it is on the cusp of tropical/subtropical, as does the storm's convection and convective organization.

A bit of history...
Since 1950, we have had just 6 storms that formed in December:
Tropical Storm #14 1953
Subtropical Storm #2 1975
Lili 1984
Odette 2003
Peter 2003
Zeta 2005

Four of those six -- ST2, Lili, Peter, and Zeta -- all formed in the subtropics from cut-off lows, largely meandering about for several days. Odette formed south-southeast of Jamaica in the Caribbean Sea and moved northeast over Hispaniola, not an uncommon track for late season storms. TS #14, however, is most similar to Olga. It formed east-northeast of the Lesser Antilles on December 7th and moved due west for two days, dissipating as it neared the northern islands on December 9th. It, like Olga, likely had hybrid origins -- probably some merger of a tropical wave and cut-off low. The other analogous storm that comes to mind, albeit one from late November, is Kate from 1985. It is highly, highly unlikely that Olga takes a path (intensity or track) anywhere similar to Kate's, but they share similar genesis locations and modes.