[NVDave]

Yes, they were.

The US Army’s mounted soldier had a maximum weight of something like 140 pounds in the 1870’s.

The Pony Express riders were thin, wiry young boys - perhaps less than 130 lbs in order to get the maximum speed and distance out of their mounts.

[knarf]

Interesting factoid I picked up some years ago ... lumberjacks back in the axe and 2 man saw days were no heavier than about 130.

Little wiry scrappy suckers.