Yes, modern violins differ in various ways from baroque ones, and most of the surviving instruments from that era were "updated." The key differences include the length of the neck, which was shorter as players didn't use as much of the range of the violin. The bridge was flatter, which made chords easier to play. And the bass bar was generally shorter, although I'm not sure what the sonic implications of that are. And possibly most important, the bows were completely different. Modern bows have a screw mechanism that keeps the tension of the hair. Before that was invented (mid 19th c.) players would keep the tension with their hand.
As for strings, modern players mostly use strings made of synthetic cores wrapped in metal. The goal is to get as close to the sound of gut as possible without all of the hassle real gut entails (expense, tempermentality, short lifespan, long break-in periods).
That said, there is a growing movement of "historical informed performance," which is the idea that we should be playing period music on period instruments, instead of our modernized versions.
As for strings, modern players mostly use strings made of synthetic cores wrapped in metal. The goal is to get as close to the sound of gut as possible without all of the hassle real gut entails (expense, tempermentality, short lifespan, long break-in periods).
That said, there is a growing movement of "historical informed performance," which is the idea that we should be playing period music on period instruments, instead of our modernized versions.