I just recently made a few D-97 strings for a Savannah and Hunters. The factory strings were alittle differnt material. I later asked Ray at BCY about this and he said is was a special blend that he did for Martin.
Martin flemish strings are better constructed than the days in the eighties when they used a simple single twisted loops. The newer strings maybe overbuilt, but of a much better quality!
To answer your question, yes you'll be fine, you can always change to a custom made string, and would'nt be a bad idea for a backup.