That sound pretty good. I don't think anyone's discussed the difference in ignition locks in this thread so far.

The early models didn't have an steering lock ignition. They had a plate that attached to the underneath of the dashboard. There was NO steering lock. This type of ignition key matched the doors. I've got a matching set from Nissan, this is what they supply when you get a 1200 keyset from them.

These ignition locks are highly insecure, as a fellow datsun owner needs to only have an ignition switch (detached from the lock by 2 screws) and a straightblade screwdriver to pull the ignition plug off the back of the existing switch/lock and connect it to his own switch, allowing him to start your car and drive away.

However, in the later (late 1971+) models, the steering lock ignition used a single sided key, as opposed to the doublesided door key.

For $45, If the locksmith can put a new barrel in the steering lock for you, I think that's a great price.

Datsun's aren't very secure cars though. I'd get deadlock doorlocks for the doors, so people can't use packing tape to open them.
I had broken doorlocks on my old car (from a failed breakin attempt using a screwdriver) I used packing tape to unlock my car for about a month. With practice it can be done regularly in under 10 seconds.

Chris.