Would a stronghold with Ender portal blocks appear in a 1.7.3 world? I haven't seen any structures yet (mineshafts, strongholds, villages) except for a nether fortress.
No they were added in the 1.8 update. If you have a 1,7,3 world and you have 1,0.0 go FAR from where the currently generated land is, there should a large flat cliff where im talking about and that is the starting point of where the strongholds, mineshafts and newer things generate.
EDIT: I'm in 1.0.0 now.
but you ould generate new chunks by walking around a little