Richard's timeline wouldn't change. Nothing about the island would change until the 70's when the bomb went off.
Dharma still existed, as we know from Ben in the alternate timeline with his dad.
As Richard's time was long before the 70's, then he wouldn't have an alternate timeline up till that point.
I don't know if the concept of "before" and "after" really apply if one is talking about a separate reality.
Consider that we already have people going back and forth in time, from one reality to another.
People were popping forwards and backwards with the flash a season or so ago.
Desmond channeled Billy Pilgrim and was popping back and forth in time in an episode a few season back.
Faraday's whole experimental gig was the movement through time.
The first thing Ben asked when he ended up in Tunisia after turning the wheel was "what year is this"?
They found the ancient polar bear remains in Tunisia (Faraday's girl friend was involved in that), which were presumably transported there backwards in time from the island.
So there clearly are plenty of time travel elements already established.
So if somehow there was an effect on Richard back in the mid 1800's, it wouldn't be without precedent.
I hadn't considered Ben's dad's comments about the island, but it was sufficiently vague that things could be very different from what has already been portrayed regarding Ben's life on the island.