Does anybody know what year foundation Bolts were required?
It depends on the actual code inspector, somewhere around the mid 90’s straps or bolts started showing up in some areas on some houses. Even now they are loosely enforced it seems. I would not make a big deal out of it unless it was still under the builders warranty period. I had a house once that was built in 1986, no straps/bolts and it got hit with 95 mph winds during hurricane Hugo. No insurance claims or issues other than a small roof leak where the shingles were already cracked.
Be advised there are some one-tab type simpson straps that “could” be used where they are only put on the outside and not visible during an inspection.
Somewhere around 1935 in CA. . .
In Florida, foundation bolts have been around for quite some time, way before 1990, probably more like 1960 or before. They have never been loosely enforced in modern day construction. Prior to foundation building code requiring anchorage via J-bolts you may have only found cut nails holding sole plates down to the foundation. The exact date that foundation bolts and their spacing became code will vary state to state. Code and warranties are completely different issues in my opinion. If I find a home that does not have continuous anchorage from truss to wall, and wall to foundation, I definately call this out. All structures should have adequate anchorage to the foundation.